U.S. patent application number 16/152176 was filed with the patent office on 2019-04-11 for electrolytic biocide generating system for use on-board a watercraft.
The applicant listed for this patent is ElectroSea, LLC. Invention is credited to Daniel L. Cosentino, Louis Ciro Cosentino.
Application Number | 20190106339 16/152176 |
Document ID | / |
Family ID | 64270937 |
Filed Date | 2019-04-11 |
View All Diagrams
United States Patent
Application |
20190106339 |
Kind Code |
A1 |
Cosentino; Louis Ciro ; et
al. |
April 11, 2019 |
ELECTROLYTIC BIOCIDE GENERATING SYSTEM FOR USE ON-BOARD A
WATERCRAFT
Abstract
The present disclosure relates to a biocide generating system
for inhibiting bio-fouling within a water system of a watercraft.
The water system is configured to draw water from a body of water
on which the watercraft is supported. The biocide generating system
includes an electrode arrangement adapted to be incorporated as
part of an electrolytic cell through which the water of the water
system flows.
Inventors: |
Cosentino; Louis Ciro; (Palm
Beach Gardens, FL) ; Cosentino; Daniel L.; (Wayzata,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ElectroSea, LLC |
Wayzata |
MN |
US |
|
|
Family ID: |
64270937 |
Appl. No.: |
16/152176 |
Filed: |
October 4, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62737555 |
Sep 27, 2018 |
|
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|
62735615 |
Sep 24, 2018 |
|
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62568629 |
Oct 5, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 2303/04 20130101;
C02F 2201/4615 20130101; C02F 1/46104 20130101; C02F 2103/02
20130101; C02F 2201/4617 20130101; C02F 2201/008 20130101; C02F
1/004 20130101; C02F 2201/4614 20130101; C02F 1/4674 20130101; C02F
2201/46145 20130101; C02F 2103/023 20130101; C02F 2103/08 20130101;
C02F 2209/40 20130101; C02F 2303/20 20130101; C02F 2103/008
20130101; C02F 2201/46175 20130101; C02F 2201/4613 20130101; C02F
2201/001 20130101 |
International
Class: |
C02F 1/461 20060101
C02F001/461; C02F 1/467 20060101 C02F001/467 |
Claims
1. A biocide generating system for inhibiting bio-fouling within a
water system of a watercraft, the water system being configured to
draw water from a body of water on which the watercraft is
supported, the biocide generating system comprising: an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows; and a
control system that interfaces with the electrode arrangement, the
control system including an electrical power circuit for
establishing a flow of electrical current between first and second
electrodes of the electrode arrangement to generate a biocide in
the water within the electrolytic cell, the control system
including a switching arrangement operable in a first switch
configuration in which the first electrode is an anode and the
second electrode is a cathode, the switching arrangement also being
operable in a second switch configuration in which the first
electrode is a cathode and the second electrode is an anode.
2. The biocide generating system of claim 1, wherein the electrical
power circuit is configured to be electrically isolated from the
watercraft.
3. The biocide generating system of claim 1, wherein the electrical
power circuit includes a constant current power supply for applying
electrical current across the first and second electrodes.
4. The biocide generating system of claim 1, wherein the control
system is configured to vary a magnitude of the electrical current
established between the first and second electrodes in relation to
a rate of water flow through the electrolytic cell.
5. The biocide generating system of claim 4, further comprising a
flow sensor for sensing the rate of water flow through the
electrolytic cell.
6. The biocide generating system of claim 4, wherein the control
system is configured to vary the magnitude of the electrical
current in proportion to the rate of water flow through the
electrolytic cell.
7. The biocide generating system of claim 4, wherein the control
system varies the magnitude of the electrical current based on an
algorithm derived from Faraday's law of electrolysis and system
dependent operating properties of the system.
8. The biocide generating system of claim 1, wherein the switching
arrangement is operable in a third switch configuration in which
electrical power is terminated to the first and second electrodes
and the first and second electrodes are electrically connected to
one another.
9. The biocide generating system of claim 8, wherein the third
switch configuration expedites transitioning electrolytic cell from
a first ion distribution wherein ions are concentrated about the
first and second electrodes to a second ion distribution in which
the ions are more uniformly distributed within the electrolytic
cell.
10. The biocide generating system of claim 9, wherein the second
ion distribution corresponds generally to a condition in which the
ions are at equilibrium and no voltage differential exists between
the first and second electrodes.
11. The biocide generating system of claim 8, wherein during
biocide generation the control system alternates the switching
arrangement between the first and second switch configuration.
12. The biocide generating system of claim 11, wherein before
switching the switching arrangement from the first switch
configuration to the second switch configuration the control system
temporarily switches the switching arrangement to the third switch
configuration, and wherein before switching the switching
arrangement from the second switch configuration back to the first
switch configuration the control system temporarily switches the
switching arrangement to the third switch configuration.
13. The biocide generating system of claim 12, wherein the
switching arrangement is operated in the first and second switching
configurations for first durations prior to switching, and wherein
the switching arrangement is operated in the third switch
configuration for a second duration before switching, wherein the
first duration is longer than the second duration.
14. The biocide generating system of claim 13, wherein the first
duration is less than or equal to 10 minutes.
15. The biocide generating system of claim 13, wherein the first
duration is in the range of 3-5 minutes.
16. The biocide generating system of claim 13, wherein the second
duration is less than or equal to 1 minute.
17-68. (canceled)
69. A biocide generating system for inhibiting bio-fouling within a
water system of a watercraft, the water system being configured to
draw water from a body of water on which the watercraft is
supported, the biocide generating system comprising: an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows; a flow
sensor for sensing a rate of water flow through the electrolytic
cell; and a control system that interfaces with the electrode
arrangement, the control system including an electrical power
circuit for establishing a flow of electrical current between first
and second electrodes of the electrode arrangement to generate a
biocide in the water within the electrolytic cell, wherein the
control system varies a magnitude of the electrical current
established between the first and second electrodes in direct
relation to the rate of water flow sensed by the flow sensor.
70. The biocide generating system of claim 69, wherein the flow
sensor is integrated with the electrolytic cell.
71. The biocide generating system of claim 70, wherein the flow
sensor is positioned adjacent an outlet of the electrolytic
cell.
72-78. (canceled)
79. A biocide generating system for inhibiting bio-fouling within a
water system of a watercraft, the water system being configured to
draw water from a body of water on which the watercraft is
supported, the biocide generating system comprising: an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows; and a
control system that interfaces with the electrode arrangement, the
control system including an electrical power circuit for
establishing a flow of electrical current between electrodes of the
electrode arrangement to generate a biocide in the water within the
electrolytic cell, the control system being configured to determine
an operational state of a pump that pumps water through the biocide
generating system, and wherein the control system is configured to
terminate the generation of biocide in relation to when it is
detected that the pump is not operating.
80. The biocide generating system of claim 79, wherein the control
system terminates the generation of biocide when it is detected
that the pump is not operating.
81-85. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Patent Application No. 62/568,629, filed Oct. 5, 2017,
U.S. Provisional Patent Application No. 62/735,615, filed Sep. 24,
2018, and U.S. Provisional Patent Application No. 62/737,555, filed
Sep. 27, 2018, the disclosures of which are hereby incorporated by
reference herein in their entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to biocide
generating systems for reducing or eliminating biofouling within
water systems. More particularly, the present disclosure relates to
an anti-biofouling system for treating the water of an on-board
water system of a watercraft.
BACKGROUND
[0003] Watercraft, particularly marine watercraft, often include
on-board water systems which use water (e.g., sea water) drawn from
the bodies of water on which the watercraft are buoyantly
supported. A prevalent type of on-board water system is configured
to pass drawn water through a heat exchanger used to cool
refrigerant associated with air conditioning systems, chillers, and
the like. Other on-board water systems include potable water
systems, sanitation systems, propulsion systems, engine cooling
systems, bait-well filling systems and systems corresponding to
ancillary equipment. Bio-fouling caused by bio-growth (e.g., marine
growth) can result in the clogging of on-board water systems, and
the inefficient operation, overheating, and malfunction of
equipment dependent upon the water systems thereby leading to
costly downtime and expensive repair. Commonly, the issue of
bio-growth within on-board water systems is addressed by periodic
(e.g., semi-annual) acid cleaning of the water systems. Acid
cleaning is expensive, time consuming, and involves the use of
harsh and hazardous chemicals. Improvements in this area are
needed.
SUMMARY
[0004] One aspect of the present disclosure relates to a biocide
generating system for inhibiting biofouling within an on-board
water system of a watercraft such that related equipment (e.g., a
heat exchanger) of the watercraft can be operated at peak
performance with minimal to no downtime. In certain examples, the
biocide generating system can include an electrolytic module for
providing the in situ generation of biocide within the water
passing through the on-board water system. In certain examples, the
biocide generating system can be continuously operated or
intermittently operated. In certain examples, a biocide generating
system in accordance with the principles of the present disclosure
eliminates the need for acid cleaning of the on-board water system,
or substantially reduces the frequency that acid cleaning of the
on-board water system is required.
[0005] Another aspect of the present disclosure relates to a
biocide generating device including an electrolytic module adapted
to fit within a canister (e.g., a strainer canister) of an on-board
water system of a watercraft. In one example, the electrolytic
module is coupled to a lid of the canister. In one example, the
electrolytic module includes electrode plates that fit within the
canister. In one example, the electrolytic module includes
electrode terminals that extend through the lid of the canister and
that are respectively electrically coupled to the electrode plates.
In a further example, a gas sensing electrode is also coupled to
the lid of the canister.
[0006] Another aspect of the present disclosure relates to a
biocide generating system having a constant current source for
providing constant electrical current across an electrolytic cell
for generating biocide.
[0007] A further aspect of the present disclosure relates to a
biocide generating system including an electrolytic cell for
generating a biocide and a controller. The biocide generating
system includes an electrical isolation circuit for electrically
isolating the biocide generating system from other conductive
components of the watercraft. In one example, the biocide
generating system includes a zero voltage reference that is
isolated relative to a ground (e.g., an earth ground) of the
watercraft. In one example, the electrical isolation circuit
inductively transfers power from a power source on the watercraft
to the biocide generating system.
[0008] Still another aspect of the present disclosure relates to a
biocide generating system including a gas sensing circuit for
detecting the accumulation of gas within an electrolytic cell of
the biocide generating system. In one example, the gas sensing
circuit includes a gas sensing electrode. In certain examples, the
gas sensing electrode mounts at an upper region of the electrolytic
cell. In certain examples, the gas sensing electrode can include at
least a portion that is submerged beneath water within the
electrolytic cell during normal operation of the biocide generating
system and that becomes exposed when gas collects in the
electrolytic cell. In certain examples, the gas sensing circuit
applies an oscillating current to the gas sensing electrode, and
the gas sensing circuit senses when an impedance between the gas
sensing electrode and another component of the electrolytic cell
changes due to exposure of the gas sensing electrode to gas. In one
example, the other component of the electrolytic cell includes an
electrode of an electrode arrangement used to generate biocide
within the electrolytic cell.
[0009] Another aspect of the present disclosure relates to a
biocide generating system for inhibiting biofouling within a water
system of a watercraft. The water system is configured to draw
water from a body of water on which the watercraft is buoyantly
supported. The biocide generating system includes an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows. The biocide
generating system also includes a control system that interfaces
with the electrode arrangement. The control system includes an
electrical power circuit for establishing a flow of electrical
current between first and second electrodes of the electrode
arrangement to generate a biocide in the water which flows through
the electrolytic cell. The control system also includes a gas
sensing circuit for detecting when gas collects in the electrolytic
cell. The control system can be configured to terminate the
generation of biocide when the collection of gas is detected.
[0010] Another aspect of the present disclosure relates to a
biocide generating system for inhibiting biofouling within a water
system of a watercraft. The water system is configured to draw
water from a body of water on which the watercraft is buoyantly
supported. The biocide generating system includes an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows. The biocide
generating system also includes a control system that interfaces
with the electrode arrangement. The control system includes an
electrical power circuit for establishing a flow of electrical
current between electrodes of the electrode arrangement to generate
a biocide in the water which flows through the electrolytic cell.
The control system also is adapted to determine when water is not
flowing through the water system, and to terminate the generation
of biocide when it has been determined that water is not flowing
through the water system. The control system can determine whether
water is flowing through the water system by various means such as
sensors (e.g., gas collection sensors, flow sensors, etc.) or by
monitoring the operational status (e.g., on or off) of the system
pump or pumps or by one or more flow sensors. When the control
system determines that water is no longer flowing through the water
system, the control system preferably terminates the generation of
biocide by terminating power to the electrode arrangement. The
control system can terminate the generation of biocide immediately
after it has been established that water is no longer flowing
through the water system. Alternatively, the control system can
allow the system to continue to generate biocide for a
predetermined time after water flow has ceased and then terminate
the generation of biocide after the predetermined time has expired.
The predetermined time can correspond to a duration that allows
sufficient biocide to be generated for an effective concentration
of the biocide to diffuse into a portion of the water system
located before of the electrolytic cell (i.e., between the
electrolytic cell and the sea-water intake of the water system) so
that bio-growth is inhibited in this portion of the water system.
In the case where the electrode arrangement is within a strainer,
the portion of the water system before the electrolytic cell
desired to be treated can extend from the strainer to the sea-water
intake of the water system. In the case where the electrode
arrangement is after the strainer, the portion of the water system
before the electrolytic cell desired to be treated can extend
through the strainer to the sea-water intake of the water system.
In the case where the electrode arrangement is after of the system
pump, the portion of the water system before the electrolytic cell
desired to be treated can extend through the pump and the strainer
to the sea-water intake of the water system.
[0011] Another aspect of the present disclosure relates to a
biocide generating system for inhibiting biofouling within a water
system of a watercraft. The water system is configured to draw
water from a body of water on which the watercraft is buoyantly
supported. The biocide generating system includes an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows. The biocide
generating system also includes a control system that interfaces
with the electrode arrangement. The control system includes an
electrical power circuit for establishing a flow of electrical
current between electrodes of the electrode arrangement to generate
a biocide in the water which flows through the electrolytic cell.
The system can be configured to generate biocide when water is
flowing through the water system. In this way, the flow of water
carries the biocide to portions of the water system located after
the electrolytic cell to inhibit bio-growth in the portion of the
water system after the electrolytic cell. The system can also be
configured to generate biocide for limited or controlled durations
when water is not flowing through the water system. In this way,
biocide generated by the electrolytic cell can diffuse from the
electrolytic cell in direction toward the sea-water inlet to treat
the portion of the water system located before the electrolytic
cell.
[0012] Another aspect of the present disclosure relates to a
biocide generating device. The biocide generating device includes a
canister lid (e.g., a strainer canister lid) and an electrode
arrangement (e.g., an electrode assembly) carried with the canister
lid for generating a biocide through electrolytic action. In
certain examples, the canister lid is adapted to attach to a
canister main body which contains a straining filter. In certain
examples, electrode plates of the electrode arrangement fit within
the straining filter. In certain examples, the electrode
arrangement includes a catalyst coating for catalyzing the
generation of chlorine. In one example, the electrode arrangement
includes electrode plates carried with the canister lid that fit
within the canister main body when the canister lid is mounted on
the canister main body. In certain examples, the electrode plates
of the electrode arrangement fit within the straining filter of the
strainer. In certain examples, the canister lid also carries a gas
sensor.
[0013] Still another aspect of the present disclosure relates to a
biocide generating system for inhibiting biofouling within a water
system of a watercraft. The water system is configured for drawing
water from a body of water on which the watercraft is buoyantly
supported. The biocide generating system includes an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows. The
electrode arrangement includes at least one anode and at least one
cathode. The biocide generating system also includes a constant
current source for establishing a flow of electrical current
between the anode and the cathode to generate a biocide in the
water which flows through the electrolytic cell. In one example,
the biocide generating system also includes an isolation circuit
for coupling the constant current source to a power source of the
watercraft.
[0014] Another aspect of the present disclosure relates to a
biocide generating system including an electrode arrangement
adapted to be incorporated as part of an electrolytic cell through
which the water of a water system flows. A control system
interfaces with the electrode arrangement. The control system
includes an electrical power circuit for establishing a flow of
electrical current between electrodes of the electrode arrangement
to generate a biocide in the water within the electrolytic cell.
The control system is configured to determine whether water is
flowing through the water system or not, and is configured to
terminate the generation of biocide in relation to when water flow
through the water system stops. In one example, the control system
terminates the generation of biocide immediately when it is
determined that water flow through the water system has stopped. In
another example, the control system terminates the generation of
biocide for a pre-determined time delay after it is determined that
water flow through the water system has stopped.
[0015] Another aspect of the present disclosure relates to a
biocide generating system including an electrode arrangement
adapted to be incorporated as part of an electrolytic cell through
which the water of a water system flows. A control system
interfaces with the electrode arrangement. The control system
includes an electrical power circuit for establishing a flow of
electrical current between electrodes of the electrode arrangement
to generate a biocide in the water within the electrolytic cell.
The control system is configured to determine whether water is
flowing through the water system or not, and is configured to
generate biocide when water is flowing through the system, and is
also configured to generate a controlled amount of biocide when the
water flow through the water system has stopped such that
sufficient biocide is generated to diffuse from the electrolytic
cell toward a water inlet of the water system. In one example, the
electrolytic cell is located between a pump and an outlet of the
water system.
[0016] A further aspect of the present disclosure relates to a
biocide generating system including a housing having a water inlet
and a water outlet. The housing defines a flow passage that extends
along a longitudinal axis of the housing between the water inlet
and the water outlet. The flow passage has a curved boundary. An
electrode arrangement is positioned within the flow passage of the
housing. The electrode arrangement is adapted to be incorporated as
part of an electrolytic cell through which the water of the water
system flows. The electrode arrangement includes interleaved
plates, each one of the plates having a length, a height and a
thickness. The lengths of the plates extend along the longitudinal
axis. The plates have different heights, and the plates have ends
that are staggered along a profile that extends along the curved
boundary of the flow passage. The plates can be staggered at only
one end of the electrode arrangement, or at both ends of the
electrode arrangement.
[0017] The present disclosure also relates to a biocide generating
system including a housing having a water inlet and a water outlet.
The housing defines a flow passage that extends between the water
inlet and the water outlet. An electrode arrangement is positioned
within the flow passage of the housing. The electrode arrangement
is adapted to be incorporated as part of an electrolytic cell
through which the water of a water system flows. The electrode
arrangement includes interleaved electrode plates having inner
major surfaces and outermost major surfaces. The inner major
surfaces are coated with a catalyst for catalyzing the generation
of chlorine and the outermost major surfaces not being coated with
the catalyst for catalyzing the generation of chlorine.
[0018] A further aspect of the present disclosure relates to a
biocide generating system including a housing having a water inlet
and a water outlet. The housing defines a flow passage that extends
between the water inlet and the water outlet. An electrode
arrangement is positioned within the flow passage of the housing.
The electrode arrangement is adapted to be incorporated as part of
an electrolytic cell through which the water of the water system
flows. The electrode arrangement includes interleaved electrode
plates. A flow diverter is provided within the flow passage for
diverting the flow of water such that the water flow is distributed
more uniformly through the electrode arrangement. In one example,
the flow diverter includes portions that extend into interstitial
spaces between the electrode plates. In one example, the
flow-diverter is a comb-like baffle having comb teeth that extend
into interstitial spaces between the electrode plates.
[0019] A further aspect of the present disclosure relates to a
biocide generating system including an electrode arrangement
adapted to be incorporated as part of an electrolytic cell through
which the water of the water system flows. The biocide generating
system also includes a control system that interfaces with the
electrode arrangement. The control system includes an electrical
power circuit for establishing a flow of electrical current between
first and second electrodes of the electrode arrangement to
generate a biocide in the water within the electrolytic cell. The
control system includes a switching arrangement operable in a first
switch configuration in which the first electrode is an anode and
the second electrode is a cathode. The switching arrangement is
also operable in a second switch configuration in which the first
electrode is a cathode and the second electrode is an anode. During
biocide generation, the control system switches the switching
arrangement back and forth between the first and second switch
configurations to inhibit the accumulation of scale on the
electrodes. In a further example, the switching arrangement is also
operable in a third switch configuration in which the first and
second electrodes are electrically connected together, and wherein
the control system temporarily switches to the third switch
configuration before switching/alternating between the first and
second switch configurations. In the third switch configuration,
the first and second electrodes can be electrically connected to a
zero voltage reference that is electrically isolated from a main
power system of the boat.
[0020] Another aspect of the present disclosure relates to a
watercraft biocide generating system including an electrode
arrangement adapted to be incorporated as part of an electrolytic
cell through which the water of the water system flows. The biocide
generating system also includes a flow sensor for sensing a rate of
water flow through the electrolytic cell, and a control system that
interfaces with the electrode arrangement. The control system
includes an electrical power circuit for establishing a flow of
electrical current between first and second electrodes of the
electrode arrangement to generate a biocide in the water within the
electrolytic cell. The control system varies a magnitude of the
electrical current established between the first and second
electrodes in direct relation to the rate of water flow sensed by
the flow sensor.
[0021] A further aspect of the present disclosure relates to a
biocide generating device including a housing defining an interior
region that extends along a central axis of the housing, an inlet
at a first side of the housing located on one side of the central
axis and an outlet at a second side of the housing located on an
opposite side of the central axis. The inlet and the outlet are
located at first and second axial positions along the central axis
that are offset from one another. The biocide generating device
also includes an electrode unit including an electrode plate
arrangement having first and second sets of electrode plates that
are interleaved with interstitial spaces defined between the
electrode plates. The electrode plate arrangement is positioned
within the interior region of the housing with open ends of the
interstitial spaces facing toward the inlet and the outlet. The
biocide generating device further includes a flow baffle positioned
within the interior region of the housing adjacent the second side
of the housing. The flow baffle is positioned at a third axial
position along the central axis that is between the first and
second axial positions. The flow baffle has a comb-like structure
with comb fingers that extend into the interstitial spaces defined
between the electrode plates.
[0022] A variety of additional aspects will be set forth in the
description that follows. The aspects can relate to individual
features and to combinations of features. It is to be understood
that both the forgoing general description and the following
detailed description are exemplary and explanatory only and are not
restrictive of the broad inventive concepts upon which the examples
described herein are based.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate aspects of the
present disclosure and together with the description, serve to
explain the principles of the disclosure. A brief description of
the drawings is as follows:
[0024] FIG. 1 illustrates a watercraft including an on-board water
system incorporating a biocide generating system in accordance with
the principles of the present disclosure;
[0025] FIG. 2 is a schematic view of a heat exchanger that is an
example of a type of equipment that can be part of the on-board
water system of the watercraft of FIG. 1;
[0026] FIG. 3 schematically depicts an electrolytic cell and
control unit of the biocide generating system of FIG. 1, wherein
the electrolytic cell is integrated as part of a water strainer of
the on-board water system;
[0027] FIG. 4 is an exploded view of the electrolytic cell of FIG.
3;
[0028] FIG. 5 illustrates a straining filter suitable for use in
the water strainer of FIG. 3;
[0029] FIG. 6 is a top view of the electrolytic cell of FIG. 3;
[0030] FIG. 7 is a top, plan view of a lid of the electrolytic cell
of FIG. 3;
[0031] FIG. 8 is cross-sectional view taken along section lines 8-8
of FIG. 7;
[0032] FIG. 9 is a perspective view of an electrode arrangement of
the electrolytic cell of FIG. 3, wherein the electrode arrangement
includes a plurality of spaced apart electrically conductive plates
which can include interleaved anode and cathode plates;
[0033] FIG. 10 is a side view of the electrode arrangement of FIG.
9;
[0034] FIG. 11 is an end view of the electrode arrangement of FIG.
9;
[0035] FIG. 12 is a side view of one of the electrically conductive
plates of the electrode arrangement of FIG. 9;
[0036] FIG. 13 is a perspective view of an electrical terminal of
the electrode arrangement of FIG. 9;
[0037] FIG. 14 depicts an example display and user interface
suitable for use with the biocide generating system of FIG. 1;
[0038] FIG. 15 depicts an example gas sensing circuit, isolation
circuit, constant current source circuit, and switching device
suitable for use with the biocide generating system of FIG. 3;
[0039] FIG. 16 illustrates a watercraft having an on-board water
system incorporating another biocide generating system in
accordance with the principles of the present disclosure;
[0040] FIG. 17 depicts an electrolytic cell of the biocide
generating system of FIG. 16;
[0041] FIG. 18 is a cross-sectional view of the electrolytic cell
of FIG. 17;
[0042] FIG. 19 depicts a watercraft having an on-board water system
incorporating another biocide generating system in accordance with
the principles of the present disclosure;
[0043] FIG. 20 is a perspective view of an electrolytic cell unit
in accordance with the principles of the present disclosure;
[0044] FIG. 21 is a cut-away view of the electrolytic cell unit of
FIG. 20;
[0045] FIG. 22 is a cross-sectional view of the electrolytic cell
unit of FIG. 20 taken along section line 22-22;
[0046] FIG. 23 is a perspective view of another electrolytic cell
unit in accordance with the principles of the present
disclosure;
[0047] FIG. 24 is a cut-away view of the electrolytic cell unit of
FIG. 23;
[0048] FIG. 25 is a cross-sectional view of the electrolytic cell
unit of FIG. 23 taken along section line 25-25;
[0049] FIG. 26 is a schematic view of the example switching device
shown in FIG. 15 arranged in a first configuration to connect the
electrolytic cell to the current source in accordance with the
principles of the present disclosure;
[0050] FIG. 27 is a schematic view of the example switching device
shown in FIG. 26 arranged in a second configuration to reverse the
polarity of the electrolytic cell in accordance with the principles
of the present disclosure;
[0051] FIG. 28 is a schematic view of the example switching device
shown in FIGS. 26 and 27 arranged in a third configuration in which
the electrodes are short circuited together to cause ions
concentrated adjacent the electrodes to move away from the
electrodes towards an equilibrium state;
[0052] FIG. 29 is an example switch configuration suitable for
performing the function of the switching device of FIGS. 26-28;
[0053] FIG. 30 is a perspective view of another electrolytic cell
unit in accordance with the principles of the present
disclosure;
[0054] FIG. 31 is an exploded view of the electrolytic cell unit of
FIG. 30;
[0055] FIG. 32 is another exploded view of the electrolytic cell
unit of FIG. 30;
[0056] FIG. 33 is an elevational view of the electrolytic cell unit
of FIG. 30;
[0057] FIG. 34 is a cross-sectional view taken along section line
34-34 of FIG. 33;
[0058] FIG. 35 is a cross-sectional view taken along section line
35-35 of FIG. 33;
[0059] FIG. 36 is a transverse cross-sectional view of the
electrolytic cell unit of FIG. 30 showing an interior flow
distribution baffle;
[0060] FIG. 37 is a transverse cross-sectional view of an example
electrode plate arrangement suitable for use with the electrolytic
cell unit of FIG. 30, the cross-sectional view shows a
cross-sectional profile or form factor of the electrode plate
arrangement;
[0061] FIG. 38 is another transverse cross-sectional view of the
electrolytic cell unit of FIG. 30 which is cut through the interior
baffle;
[0062] FIG. 39 is another transverse cross-sectional view of the
electrolytic cell of FIG. 30 showing the relative positioning of
the electrode plate arrangement with respect to the inlet and the
outlet of the electrolytic cell;
[0063] FIG. 40 is a top end view of the electrolytic cell of FIG.
30 with a top lid removed;
[0064] FIG. 41 is a cross-sectional view of the electrolytic cell
of FIG. 30 showing the relative axial positioning of the baffle
with respect to the inlet and the outlet of the electrolytic
cell;
[0065] FIG. 42 is a graph depicting control protocol including a
repeating pattern for controlling the application of current across
the electrodes of the electrolytic cell;
[0066] FIG. 43 schematically depicts another biocide generating
system in accordance with the principles of the present disclosure;
and
[0067] FIG. 44 is a more detailed schematic of the biocide
generating system of FIG. 43.
DETAILED DESCRIPTION
[0068] FIG. 1 illustrates a watercraft 20 having an on-board water
system 22 including a biocide generating system 24 in accordance
with the principles of the present disclosure. The watercraft 20 is
shown supported on a body of water 26. The on-board water system 22
includes an inlet 28, an outlet 30, and a water flow path 32 that
extends from the inlet 28 through the watercraft 20 to the outlet
30. The inlet 28 is configured for drawing water from the body of
water 26 into the water flow path 32. The inlet 28 is located below
a water line 34 of the watercraft 20 and is preferably located at a
bottom of the hull of the watercraft 20. The inlet 28 can be opened
and closed by a valve 36 such as a seacock. The outlet 30 is
configured for discharging water that has passed through the water
flow path 32 back to the body of water 26. Preferably, the outlet
30 is positioned above the water line 34. The on-board water system
22 can include a plurality of components positioned along the water
flow path 32. The water flow path 32 can include a plurality of
conduits 38 (e.g., hoses, tubes, pipes, etc.) which extend between
the components of the on-board water system 22 and function to
carry water along the water flow path 32 between the various
components. As shown at FIG. 1, the depicted components include a
water strainer 40, a pump 42, and one or more systems and/or
equipment 44 that make use of water conveyed through the water flow
path 32.
[0069] In the depicted example, the biocide generating system 24
includes an electrolytic cell 46 integrated with the strainer 40.
The electrolytic cell 46 interfaces with a control unit 48 (e.g.,
controller) and is adapted for generating a biocide within the
water of the water flow path 32 while the water passes through the
strainer 40. The biocide is configured for inhibiting biofouling
within the conduits 38 and within one or more of the components
positioned along the water flow path 32. It will be appreciated
that the biocide can also be referred to as a disinfecting agent or
a cleaning agent since the biocide can also include disinfecting
and cleaning properties.
[0070] It will be appreciated that examples of the type of the
systems and/or equipment 44 that can benefit from biocide treatment
can include cooling systems such as air conditioners or chillers
where water drawn from the body of water 26 can be used as a
cooling media for cooling refrigerant of the cooling systems. FIG.
2 shows an example piece of equipment 44 in the form of a heat
exchanger for a cooling system such as an air conditioner or other
cooling system. Within the heat exchanger, water from the water
flow path 32 flows across coils 50 or other conduits through which
refrigerant corresponding to the cooling system flows. As the
refrigerant flows through the coils 50, the water in the heat
exchanger cools the refrigerant within the coils 50. In other
examples, the water from the water flow path 32 can be used to
provide engine cooling. In other examples, water from the water
flow path 32 can be used for sanitation systems or watercraft
propulsion systems.
[0071] In certain examples, the water flow path 32 may provide
water to water systems for which biocide is not desired. Example
water systems can include potable water systems for providing
drinking water (drinking water systems often include reverse
osmosis filtration systems that are not compatible with significant
levels of chlorine), shower water, water for faucets, or other
potable water uses on the water vessel. Additionally, water from
the water flow path 32 can be used for live well systems to fill
live wells for holding bait on the watercraft 20. An example water
system 47 of the type mentioned above which is not compatible with
biocide and which draws water from the flow path 32 is shown at
FIG. 1. A valve 49 can be used to open and close fluid
communication between the main water flow path 32 and the water
system 47. When water systems that are incompatible with the
presence of biocide in the water are in need of water from the
water flow path, power to the electrolytic cell of the biocide
generating system 24 can be temporarily turned off (e.g., the
system can be operated in an inhibit mode) so as to inhibit the
generation of biocide. It will be appreciated that the control unit
48 can interface with such water systems and can automatically
disable (i.e., turn off; operate in an inhibit mode) the biocide
generating system 24 when water is needed for a potable water
system, a bait well, or other water system where biocide is not
desired. For example, when the water system 47 incompatible with
biocide is activated (e.g., when valve 49 is opened), the system
can initiate an activate water command/signal which is received by
the controller 48 and used as a trigger for initiation of the
inhibit mode. After the demand for water by the incompatible water
system has been satisfied (e.g., when valve 49 is closed), the
system can issue a deactivate water command/signal which is
received by the controller 48 and used as a trigger for resuming
the generation of biocide. Referring to FIG. 1, the valve 49 can
interface with a processor 248 that stops electrical power from
being supplied to the electrolytic cell 46 when the valve 49 is
open and permits power to be provided to the electrolytic cell 46
when the valve 49 is closed.
[0072] In the example of FIG. 1, the watercraft 20 is shown with
only one on-board water system 22. In other examples, watercraft
may include multiple on-board water systems each having one or more
pumps that operate independently of one another. It will be
appreciated that separate biocide generating systems 24 can be
incorporated into each of the on-board water systems of the
watercraft and can be controlled by a common control unit.
[0073] It will be appreciated that biocide generating systems in
accordance with the principles of the present invention can be used
for watercraft launched in both saltwater and freshwater. However,
a preferred biocide in accordance with the aspects of the present
disclosure includes chlorine generated through the electrolysis of
sea water. Therefore, for freshwater watercraft, biocide generating
systems in accordance with the principles of the present disclosure
can include a salt supplementing station where salt such as sodium
chloride is added to the water of the on-board water system 22
before the electrolytic cell of the biocide generating system. For
marine watercraft, the natural salt present in sea water or
brackish water is sufficient to allow for the in situ generation of
biocide within the water flowing through the water flow path 32.
For freshwater applications, it is contemplated that other biocides
such as copper could also be used. In such systems, an electrolytic
cell including electrodes of copper can be used to introduce copper
as a biocide into the water of the water flow path 32.
[0074] As indicated above, a preferred biocide generated by biocide
generating systems in accordance with the principles of the present
disclosure includes chlorine and/or a derivative thereof. Other
biocides can also be generated dependent upon the type of salts
present in the water. The process for generating biocide can
include an in situ process where sea water (e.g., ocean water,
brackish water, etc.) is subjected to electrolysis as the sea water
flows through an electrolytic cell. The electrolytic cell can
include electrodes defining an anode (e.g., a positive pole) and a
cathode (e.g., a negative pole). The direct passage of electrical
current through the sea water between the anode and the cathode
drives electrolysis that separates the water and the salt into
their basic elements. In certain examples, chlorine is generated at
the anode and hydrogen is generated at the cathode. The chlorine
generated at the anode and/or derivatives thereof can function as a
biocide for inhibiting bio growth in conduits and equipment of the
water flow path located after from the electrolytic cell.
[0075] In certain examples, biocide generating systems in
accordance with the principles of the present disclosure can
include control circuitry for controlling operation of first and
second electrodes in a manner that inhibits or resists the
accumulation of scale (e.g., precipitation-based scale such as
calcium carbonate, calcium hydroxide, magnesium hydroxide, and the
like) on the first and second electrodes. Typically, scaling is
prone to occur at the cathode of the electrolytic cell because of
the alkaline characteristic of the water at the cathode-water
interface, but is not prone to occur at the anode because of the
lower pH (e.g., acidic characteristic) of the water at the
anode-water interface. By alternating the polarity of the first and
second electrodes, the first and second electrodes can be switched
back and forth between anodes and cathodes. When a given one of the
electrodes is operated as an anode, the lower pH of the water at
the anode-water interface can assist in dissolving scale that may
have been formed on the electrode when the electrode was previously
operated as a cathode. Thus, continuously switching the polarity of
the first and second electrodes inhibits the accumulation of scale
on the electrodes to a level in which the performance or efficiency
of the electrolytic cell is compromised. In one example, the
electrolytic cell has an undivided arrangement in which the first
and second electrodes are not separated by a membrane.
[0076] In certain examples, the biocide generating system
alternates operation of the electrolytic cell between a forward
biocide generating state and a reverse biocide generating state. In
the forward biocide generating state, the first electrode is
operated as an anode and the second electrode is operated as a
cathode such that current flows in a forward direction between the
first and second electrodes through the sea water within the
electrolytic cell causing the generation of biocide in the sea
water. In the reverse biocide generating state, the first electrode
is operated as a cathode and the second electrode is operated as an
anode such that current flows in a reverse direction between the
first and second electrodes through the sea water within the
electrolytic cell causing the generation of biocide in the sea
water. It will be appreciated that as the biocide generating system
is operated in a given one of the forward and reverse biocide
generating states, an ion concentration gradient can develop and
increase in intensity over time within the electrolytic cell. For
example, the concentration of certain negative ions (e.g.,
Cl.sup.-) can increase adjacent the anode and the concentration of
certain positive ions (e.g., Na.sup.+) can increase adjacent the
cathode.
[0077] Aspects of the present disclosure relate to operating the
electrolytic cell in each of the forward and reverse biocide
generating states for a relatively short duration (e.g., less than
or equal to 10 minutes, or less than or equal to 8 minutes, or less
than or equal to 6 minutes, or less than or equal to 5 minutes)
before alternating the biocide generating state. By alternating the
electrolytic cell between the forward and reverse biocide
generating states relatively frequently (i.e., by keeping the
operating durations of the first and second biocide generating
states relatively short), the ion gradient within the electrolytic
cell is frequently reversed, which assists in the efficient and
effective scale-free operation of the electrolytic cell.
[0078] The biocide generating system can also be operated
temporarily in an ion re-distribution state adapted to facilitate
movement or re-arrangement or equilibration of ions within the
electrolytic cell from a first ion distribution in which ions in
the sea water within the electrolytic cell are concentrated near
the electrodes to a second ion distribution in which the ions are
more uniformly distributed within the sea water of the electrolytic
cell. The second ion distribution ideally represents the ion
distribution in the water of the electrolytic cell corresponding to
a condition in which no difference in electric potential exists
between the first and second electrodes and the ions and/or the ion
concentration in the electrolyte within the electrolytic cell are
at equilibrium and uniformly distributed. In a preferred example,
the biocide generating system can be operated in the
ion-redistribution state for a time period between the forward and
reverse biocide generating states, and can also be operated in the
ion-redistribution state for a time period between the reverse and
forward biocide generating states. When electrical current is
applied across the first and second electrodes during the forward
or reverse biocide generating states, the ions within the water of
the electrolytic cell migrate toward the electrodes of the opposite
pole (e.g., negative ions migrate toward the anode while positive
ions migrate toward the cathode) causing the ions to be arranged in
the first ion distribution. When the electrolytic cell is operated
in the ion re-distribution state, electrical current is no longer
driven across the first and second electrodes by the electrical
power source (e.g., the electrical power is disconnected from the
electrodes and/or no difference in electric potential is provided
between the first and second electrodes), and the first and second
electrodes are electrically connected together to provide an
electrical short between the first and second electrodes. When the
electrical current is no longer applied across the first and second
electrodes, the ions have a tendency to move toward an equilibrium
state in which the ions in the electrolyte (e.g., the sea water)
are uniformly distributed in the electrolytic cell. Concurrently,
water flow through the electrolytic cell can wash ions away from
the electrodes. By terminating electrical power to the electrodes
and concurrently electrically connecting the first and second
electrodes together, the rate of movement of the ions toward the
second ion distribution is expedited as compared to the rate of ion
movement that would occur by only terminating electrical power to
the electrodes. In certain examples, electrically connecting the
first and second electrodes together results in the expedited
movement of ions in the electrolyte toward an equilibrium state
(e.g., ions that had been concentrated adjacent the electrodes
during biocide generation move away from the electrodes to provide
a more uniform distribution of ions in the electrolyte). In certain
examples, the first and second electrodes are concurrently
connected to a zero voltage reference of an electrical power system
of the electrolytic cell (e.g., a power system that provides
electrical power to the electrodes) when the electrolytic cell is
in the ion re-distribution state. The zero voltage reference is
electrically isolated from a main ground of the boat by a
transformer or the like.
[0079] FIG. 42 is a graph showing electrical current applied across
the first and second electrodes over time. The graph is
representative of a control protocol for controlling the
application of electrical current across the first and second
electrodes. The control protocol can use a repeating pattern of
operating states. Referring to FIG. 42, the repeating pattern
includes a forward biocide generating operating state (see 920),
followed by an ion re-distribution operating state (see 922a),
followed by a reverse biocide generating operating state (see 924),
followed by the ion-redistribution state (see 922b). Thereafter,
the pattern is repeated as biocide is generated.
[0080] It is preferred for a constant electrical current source to
be used as an electrical power source for applying the electrical
current across the first and second electrodes during biocide
generation. It will be appreciated that the ability to provide
constant current with a constant current electrical power source is
dependent upon the resistance of the load and the capacity of the
power source. Thus, at low load resistances, a constant current
source may not be able to provide constant current if it lacks
sufficient electrical voltage. Referring to FIG. 42, the depicted
electrical current profile is shown assuming ideal conditions. In
actual practice, variations may exist and the current profile may
deviate from the depicted current profile. It will also be
appreciated that the voltage applied across the electrodes can
ramp-up over time and then stabilize each time one of the forward
or reverse biocide generating operating states is initiated.
[0081] In one example, the control circuitry can include one or
more switches for alternating the polarity of the first and second
electrodes. In certain examples, the control circuitry can
alternate the electrodes back and forth between a first polarity
state and a second polarity state. In alternating the polarity of
the electrodes, an intermediate state (e.g., an ion re-distribution
state) can be implemented temporarily between the first and second
polarity states. In the first polarity state, the first electrode
functions as an anode and the second electrode functions as a
cathode. In contrast, in the second polarity state, the first
electrode functions as a cathode and the second electrode functions
as an anode. Preferably, the control system alternates (e.g.,
reverses) the polarity state of the electrodes after the electrodes
have been active in one of the polarity states for a duration of
time. In one example, the duration the electrodes are operated in
the first polarity state before switching to the second polarity
state is equal to the duration the electrodes are operated in the
second polarity state before switching back to the first polarity
state. In one example, the duration the electrodes are operated in
the first polarity state before switching to the second polarity
state does not deviate by more than 5, 10 or 20 percent as compared
to the duration the electrodes are operated in the second polarity
state before switching back to the first polarity state. In one
example, over an extended operating period (e.g., a week or a
month), the electrolytic cell generates biocide in the first
polarity state for the same or about the same amount of time in
which the electrolytic cell generates biocide in the second
polarity state. In one example, over an extended operating period
(e.g., a week or a month), the amount of time electrolytic cell
generates biocide in the first and second polarity states does not
deviate by more than 5, 10 or 20 percent. In a preferred example,
water continues to flow through the electrolytic cell and the
electrolytic cell continues to generate biocide for use in
preventing bio-growth in the boat water system as the electrolytic
cell is operated in both the first and second polarity states.
[0082] In one example, over an extended operating period, the
electrolytic cell is continuously switched back and forth between
the first and second polarity states. Each time the electrolytic
cell is switched to the first polarity state, the electrolytic cell
is operated for a first set duration d1 (see FIG. 42) in the first
polarity state before switching from the first polarity state to
the second polarity state. Similarly, each time the electrolytic
cell is switched to the second polarity state, the electrolytic
cell is operated for the first set duration d1 in the second
polarity state before switching from the second polarity state to
the first polarity state. It will be appreciated that the system
may not switch directly from the first polarity state to the second
polarity state or vice-versa. For example, in switching between the
first and second polarity states, an intermediate state (e.g., an
ion re-distribution state) may be implemented temporarily between
the first and second polarity states. The first set duration is
preferably long enough to allow the electrodes to fully charge and
for biocide to be generated. The first set duration is preferably
short enough to inhibit scaling. In one example, the first set
duration is less than or equal to 10 minutes, or in the range of
1-10 minutes, or in the range of 2-10 minutes, or in the range of
2-8 minutes, or in the range of 2-6 minutes, or in the range of 3-5
minutes.
[0083] In certain examples, once the electrodes have been active in
one polarity state for the first set duration, electrical power to
the electrodes is terminated and the first and second electrodes
are electrically connected together prior to reversing the polarity
state of the electrodes. In one example, the first and second
electrodes can be electrically connected together and to a zero
voltage reference (e.g., a zero voltage reference that is
electrically isolated from the ground of the main power system of
the boat). In one example, electrically connecting the first and
second electrodes together while electrical power is terminated to
the electrodes can expedite the transfer of ions in the sea water
within the electrolytic cell away from the electrodes to provide a
more uniform distribution of ions in the sea water (e.g., the ions
move toward equilibrium). In one example, the first and second
electrodes can be electrically connected together for a second set
duration d2 (see FIG. 42) before switching to the subsequent first
or second polarity state. In certain examples, the second set
duration d2 is long enough for localized concentrations of ions
adjacent the electrodes to move away from the electrodes to provide
a more uniform distribution of ions within the electrolyte. In
certain examples, when the electrical power is terminated and the
first and second electrodes are electrically connected together,
the ions in the sea water within the electrolytic cell move toward
a uniform ion distribution that would be expected when the ions of
the cell are at equilibrium and no difference in electric potential
(e.g., voltage differential) exists between the electrodes. In
certain examples, the second set duration d2 is shorter than the
first set duration in which the electrodes are operated in the
first and second polarity states. In certain examples, the second
set duration is less than 2 minutes, or less than 1 minute, or less
than 45 seconds, or about 30 seconds.
[0084] In certain examples of the present disclosure, electrolytic
cells in accordance with the principles of the present disclosure
can include electrode arrangements each including first and second
electrodes. The first electrode can include a plurality of first
electrode plates and the second electrode can include a plurality
of second electrode plates. The first and second electrode plates
can be interleaved with respect to one another such that
interstitial spaces are positioned between each of the first and
second electrode plates. The saltwater flowing through the water
flow path flows within the interstitial spaces and is electrolyzed
as the water flows through the interstitial spaces such that
chlorine is generated. In certain examples, each of the electrode
plates includes an electrically conductive material such as a metal
material. In one example, the metal material may include titanium.
In certain examples, the electrode plates can be coated with a
catalyst coating adapted to catalyze the generation of chlorine. In
one example, the catalyst coating can include a platinum group
metal. Example platinum group metals suitable for use in a catalyst
coating include iridium and ruthenium. In certain examples, the
catalyst coating may include metal oxide mixtures that can include
oxides of iridium, and/or oxides of ruthenium and/or oxides of
titanium and/or oxides of tantalum and/or oxides of niobium. It
will be appreciated that the above catalysts are merely examples
and that other catalyst mixtures can also be used. In certain
examples, the catalyst coating including metal oxide mixtures may
not be applied to the outside major surfaces of the outermost
electrode plates in the electrolyte cell. Eliminating the coating
on the outside major surfaces can help to reduce and/or eliminate
scale build-up.
[0085] It will be appreciated that in certain examples, the biocide
generating system 24 is adapted to inhibit the growth of bio matter
within the water flow path 32. Thus, the biocide generating system
can be configured to regularly provide biocide to the water flowing
through the water flow path 32. In certain examples, when the
biocide generating system is active (i.e., turned on and not in an
inhibit mode where biocide generation is inhibited) the biocide
generating system 24 can be continuously operated to provide
biocide to the water of the water flow path when water is flowing
through the water flow path 32. In other examples, when the biocide
generating system is active, the biocide can be intermittently
generated so that biocide is provided with sufficient frequency to
inhibit the growth of bio matter. For the regular treatment of
water within the water flow path 32 so as to inhibit the growth of
bio matter, the biocide generating system can generate biocide at
concentrations in the range of 0.1-5.0 parts per million, or at
concentrations in the range of 0.1-2.0 parts per million, or at
concentrations in the range of 0.1-1.0 parts per million, or in
concentrations in the range of 0.1-0.5 parts per million. As
indicated above, a preferred biocide includes chlorine. To minimize
the discharge of residual chlorine from the water system, the
biocide generating system 24 may be designed to generate only
enough chlorine needed to inhibit the growth of bio matter. In
certain examples, the chlorine concentration does not exceed 1.0
parts per million within the water system, although alternatives
are possible.
[0086] It will be appreciated that the rate at which biocide is
generated is directly dependent upon the magnitude of the
electrical current directed across the electrodes. Also, the amount
of biocide generated is dependent upon the amount of time the cell
is generating biocide. Further, the concentration of biocide
generated in the electrolyte (e.g., sea water or other salt water)
flowing through the system is dependent upon water flow rate. Thus,
the concentration of biocide present in the flowing electrolyte of
the system can be controlled by varying the current level across
the electrodes and/or cycling the cell On and Off to vary the time
of operation of the cell and/or varying the water flow rate through
the system. In certain examples, the water flow rate through the
system is monitored, and the electrical current level and/or the
time of operation of the cell are varied (e.g., controlled,
regulated, etc.) to achieve a target biocide concentration in the
water of the system. It will be appreciated that the water flow
rate can be determined based on flow information derived from the
pump control or by one or more flow sensors. An example flow sensor
can include a flow meter such as a hall-effect flow sensor (e.g.,
an electronic paddle flow meter). In certain examples, the flow
meter can be provided at or in the electrolytic cell. In certain
examples, the flow meter can be provided at an outlet of the
electrolytic cell. In a preferred example, the biocide
concentration in the electrolyte is maintained at a level
sufficiently high to kill bio-matter and sufficiently low to avoid
damaging corrosion within system. A preferred chlorine
concentration is less than or equal to 2 ppm, or less than or equal
to 1 ppm, or less than or equal to 0.5 ppm, or less than or equal
to 0.3 ppm, or less than or equal to 0.2 ppm or in the range of
0.1-0.2 ppm.
[0087] As indicated above, the biocide generating system 24 can
automatically be cycled On and Off to control the amount of
chlorine generated, or can vary the electrical current to vary the
amount of chlorine generated. The controller 48 may be configured
to regulate the operation of the biocide generating system 24 to
achieve a desired or target amount of chlorine. In certain
examples, the controller 48 can regulate the amount of chlorine
generated based at least partially on a measured flow rate of the
seawater flowing through the electrolytic cell for
electrolysis.
[0088] In certain examples, pulsing the current to the electrodes
On and Off results in slugs of chlorine treated water passing
through the system, rather than a continuous flow of water having a
constant chlorine concentration. In other examples, the total
output of chlorine is controlled independent of the seawater flow
rate through the electrolyte unit.
[0089] In certain examples, chlorine sensors 602 (see FIGS. 1 and
15) for sensing chlorine concentration in the water can be provided
at one or more locations along the flow path of the water system.
For examples, the sensors 602 can be positioned at the electrolytic
cell unit, at the seawater outlet, or at other positions along the
flow path of the water system. The controller 48 can interface with
the sensors 602 and can use chlorine concentration data from the
sensors 602 to control or vary operation of the electrolytic cell.
For example, based on the sensed chlorine concentration or
concentrations, the controller can increase or decrease water flow
rate through the electrolytic cell unit and/or the electrical
current provided to the electrolytic cell unit and/or an On and Off
pulse duration of the cell unit. In this way, the controller can
modify the rate of biocide generation and/or the water flow rate of
the system in real time to maintain a desired chlorine
concentration throughout the system or at discrete locations in the
system. Moreover, the controller can control operation of the
system so that the residual chlorine in the water discharged from
the outlet 30 does not exceed a predetermined concentration
level.
[0090] For different applications, biocide concentrations higher or
lower than the above specified concentrations may be generated. For
example, under certain circumstances, it may be desired to "shock"
the water flow path 32. For such applications, the biocide
generating system 24 can generate significantly higher
concentrations of biocide as needed.
[0091] In a preferred example, the biocide generating system 24
includes an adaptive dynamic control system that dynamically varies
the magnitude of the current applied across the electrodes in
direct proportion to the flow rate of water through the
electrolytic cell. Thus, the rate of biocide production varies
directly with the water flow rate through the system. The magnitude
of electrical current used to provide a desired biocide
concentration in the flow of sea water through the electrolytic
cell for a given water flow rate can be determined by a method such
as an algorithm or look-up table. The flow rate can be determined
by a flow sensor 51 (see FIGS. 1, 3 and 15). In one example, the
flow sensor 51 is integrated with/attached to the electrolytic
cell. In one example, the flow sensor 51 can be mounted adjacent to
the outlet of the electrolytic cell to prevent bio-growth from
damaging or fouling the flow sensor. By dynamically controlling the
rate of biocide generation, it is possible to maintain the
concentration of biocide at a target level or within a target range
regardless of the water flow rate. Thus, at low flow rates, the
biocide production rates can be reduced accordingly to maintain the
biocide concentration within the target range thereby preventing
biocide concentrations from increasing to a level which could be
damaging to components of the system (e.g., via corrosion). For
example, parts such as heat exchangers can include copper-nickel
alloy parts that may be susceptible to corrosion. At low flow
rates, the biocide production rates can be reduced accordingly to
maintain the biocide concentration within the target range thereby
preventing biocide concentrations from decreasing to a level
ineffective for killing bio-organisms.
[0092] The biocide production rates can be controlled using an
application of Faraday's law of electrolysis which teaches that the
amount of a chemical consumed or produced at one of the electrodes
in an electrolytic cell is directly proportional to the amount of
electrical current that passes through the cell. One coulomb of
charge equates to one ampere per second, and Faraday's constant of
96,485 coulombs represents the number of coulombs of electrical
charge carried by one mole of electrons. Thus, 96,485 coulombs will
produce one mole of Cl.sup.- at an electrode of the electrolytic
cell. Taking this information into consideration in combination
with the water flow rate through the electrolytic cell, it is
possible to calculate the electrical current required to pass
through the electrolytic cell to generate a desired concentration
of biocide in the sea water passing through the electrolytic
cell.
[0093] An example formula (see below) derived from the above
information specifies that the electrical current (A) required to
pass through the electrolytic cell to generate a desired
concentration (C) of Chlorine in the sea water flowing through the
electrolytic cell equals the desired concentration (C) of Chlorine
multiplied by the water flow rate (Q) divided by 5.75. The value K
represents a system specific constant that takes into consideration
operating properties of electrolytic cell (e.g., inefficiencies
related biocide conversion at the electrodes) as well as the
characteristics of the electrolyte (e.g., sea water quality, levels
of organic material in the sea water which may react with the
biocide, etc.). In certain examples, K can be empirically
determined.
A = K .times. C .times. Q 5.75 ##EQU00001##
Where
[0094] A=electrical current passing through the sea water between
the electrodes of the electrolytic cell in amperes [0095] C=desired
concentration of chlorine to be generated in the sea water passing
through the electrolytic cell in parts-per-million [0096] Q=flow
rate of sea water through the electrolytic cell in gallons per
minute [0097] K=system specific constant
[0098] The biocide generating system 24 preferably operates to
generate biocide while water is flowing through the water system.
In this way, biocide generated at the electrolytic cell 46 can be
carried with the flowing water to treat the conduit and components
of the water system located after the electrolytic cell. As
indicated above, biocide can be generated continuously or
intermittently as the water flows through the system. In certain
examples, the biocide generating system may also operate to
generate biocide for a controlled or limited duration when water is
not flowing through the water system (e.g., when the pump is off).
The duration preferably corresponds to sufficient time for the
system to generate enough biocide for the biocide to diffuse from
the electrolytic cell 46 toward the sea-water inlet of the water
system to prevent bio-growth within the portion of the water system
located before the electrolytic cell 46. Preferably, the duration
is short enough to prevent the excessive accumulation of gas within
the system. In certain examples, the duration can be in the range
of at least thirty seconds to at least five minutes. In other
examples, the duration can be in the range of thirty seconds to ten
minutes, in the range of thirty seconds to seven minutes, in the
range of thirty seconds to five minutes, or in the range of thirty
seconds to two minutes. In certain examples, the biocide generating
system may operate intermittently to generate biocide while water
is not flowing through the system so as to generate enough biocide
to treat the portion of the water system before the electrolytic
cell via diffusion without collecting excessive gas within the
system (e.g., within the strainer). Preferably, for a majority of
the time that water is not flowing through the water system, the
biocide generating system will not be generating biocide.
[0099] Referring to FIG. 3, the control unit 48 (i.e., a
controller, control system, etc.) is depicted including the
processor 248 which is shown interfacing with a user interface 250,
a display 252, a sensing circuit 254, a cell power circuit 256, and
an isolation circuit 258. In certain examples, the user interface
250 and the display 252 can be separate units or can be integrated
in a common unit. The user interface may include buttons, keypads,
switches, dials, touch screens, or like structures for allowing a
user to input information, turn the system 24 on and off, and
modify operational settings of the system 24. The display may
include indicator lights, display screens, audible indicators, or
other features for indicating operating states, modes, conditions,
or parameters of the system 24. The sensing circuit 254 can be
configured to detect/sense the accumulation of gas within the
electrolytic cell 46. The cell power circuit 256 can be configured
to supply electrical power to the electrolytic cell 46 (e.g., to
electrodes of the electrolytic cell 46). The processor 248 can
interface with a switch for turning the power to the electrolytic
cell 46 on and off. In one example, the cell power circuit 256
includes a constant current source for driving a constant current
through the electrolytic cell 46 which is not dependent upon the
load across the electrolytic cell or the applied voltage. The
magnitude of the constant current provided by the constant current
source can be varied by the controller to regulate the amount of
biocide generated by the system. The isolation circuit 258
transfers power from a power source 262 on the watercraft 20 to the
biocide generating system 24 and concurrently provides the biocide
generating system 24 with a zero voltage reference 264 that is
electrically isolated from an earth ground 266 of the watercraft
20.
[0100] As shown at FIGS. 3 and 4, the electrolytic cell 46 is
integrated with the water strainer 40. It will be appreciated that
a water strainer is a device that mechanically filters the water
drawn into the water flow path 32 to prevent undesirable material
(e.g., particulates over a certain size) from passing through the
water flow path 32. It will be appreciated that water strainers
typically include removable filters that are periodically removed
from the strainer, cleaned and then returned to the strainer. It
will be appreciated that different filters can have different
levels of filtration ranging from coarse to fine. Additionally,
filters can have different configurations depending upon the type
of strainer used. Some types of filters can include a basket type
configuration. Other filters can be configured as cylindrical
sleeves. It will be appreciated that water strainers may also
include a flow diverter to help create laminar flow or to assist in
providing more uniform flow through the electrolytic cell. For
example, to reduce scaling, it is desirable to limit eddies,
recirculation and dead/stagnant flow areas (e.g., areas of low
flow) through the electrolytic cell. For example, it is desirable
to encourage more uniform flow between all the plates of the
electrolytic cell and across the entire flow area (the
cross-sectional area defined between the plates as shown at FIG.
11) defined by the electrolytic cell. A flow diverter may help to
provide uniform flow within the system such that seawater does not
only flow directly thru a limited portion (e.g., a top part) of a
water strainer. One advantage of using a flow diverter in
accordance with the principles of the present disclosure is that
such use can decrease or eliminate scale build-up. In certain
examples, a flow diverter may be included as an attachment to an
electrolyte cell. In certain examples, a strainer containing an
electrolytic cell may have an in-line inlet and outlet to encourage
more uniform water flow through the strainer.
[0101] The depicted strainer 40 of FIGS. 3 and 4 includes a housing
52 (e.g., a strainer canister) including a main housing body 54 and
a lid 56 (e.g., a strainer lid). The lid 56 is preferably removable
from the main housing body 54 and can also be referred to as a
cover. In certain examples, the lid 56 is removably mounted at a
top of the main housing body 54. In certain examples, fasteners
such as bolts, nuts, clips, clamps, or other structures can be used
to removably attach the lid 56 to the main housing body 54. In
certain examples, the housing 52 has a metal construction. The
metal construction can include stainless steel. In other examples,
one or more components of the housing 52 can have a dielectric
construction. The dielectric construction can include a composite
construction where an electrically conductive material is coated
with a dielectric material, or a composite construction where
portions of the housing are electrically conductive and portions
are dielectric. Dielectric constructions can also include solid
dielectric constructions.
[0102] The main housing body 54 includes a water inlet 58 and a
water outlet 60. As depicted, the water inlet 58 is elevated
relative to the water outlet 60. In other examples, other outlet
and inlet configurations can be used. For example, in another
example, the water inlet can extend through the bottom of the
housing and the water outlet can extend through the side of the
housing.
[0103] Referring to FIGS. 4 and 5, the strainer 40 includes a
straining filter 62 that removably mounts within an interior 64 of
the housing 52. As depicted, the straining filter 62 has a
basket-like configuration. The straining filter 62 is depicted
including a filtering media 66 and a top flange 68. When mounted
within the housing 52, the top flange 68 can seat upon a shoulder
or other structure of the housing 52 to provide for exact
positioning of the straining filter 62. An opening 70 is defined
through the side of the filter media 66. When the straining filter
62 mounts within the housing 52, the opening 70 preferably aligns
with the water inlet 58 of the main housing body 54. Thus, in use,
water being conveyed through the water flow path 32 enters the
housing 52 through the water inlet 58 and enters an interior of the
straining filter 62 through the opening 70. The water then passes
through the filter media 66 and exits the housing 52 through the
water outlet 60. Particulate materials strained by the filter media
66 remains on an inside of the filter media 66. When the straining
filter 62 is removed from the housing 52, the strained material
remains on the inside of the filter media 66 and is preferably
removed during cleaning.
[0104] While the straining filter 62 is depicted as a basket-style
filter, it will be appreciated that other types of straining
filters can be used, particularly when used in combination with
other styles of strainer housings. For example, cylindrical
straining filters having open bottoms can be used with strainer
housings having bottom inlets and side outlets. In such
configurations, the straining filters have interior regions in
which the filtered material collects.
[0105] Referring to FIGS. 3, 4, and 9-13, the electrolytic cell 46
includes an electrode arrangement 72 integrated with the strainer
40 such that electrolysis of the water of the water flow path 32
occurs within the interior volume of the strainer housing 52. The
electrode arrangement 72 can also be referred to as an electrolytic
module. In the depicted example, the electrode arrangement 72
includes a first electrode 74 and a second electrode 76. The first
electrode 74 includes a first terminal 78 electrically coupled to a
plurality of parallel first electrode plates 80. The first terminal
78 includes a first terminal block 82 and a first terminal post 84.
The first electrode plates 80 are electrically and mechanically
coupled to the first terminal block 82. In one example, the first
electrode plates 80 include main bodies 86 and upper tabs 88. The
upper tabs 88 are preferably electrically and mechanically coupled
to the first terminal block 82 by means such as welding or
soldering. In certain examples, the first terminal 78 and the first
electrode plates 80 can have metal constructions that include a
metal material such as titanium. In certain examples, the first
electrode plates 80 can be coated with a catalyst material of the
type previously described.
[0106] The second electrode 76 of the electrode arrangement 72 has
a similar configuration as the first electrode 74. For example, the
second electrode 76 includes a second terminal 90 and parallel
second electrode plates 92 that are electrically and mechanically
coupled to the second terminal 90. In a preferred example, the
second terminal 90 and the second electrode plates 92 have metal
constructions that may include a metal material such as titanium.
The second electrode plates 92 are positioned between the first
electrode plates 80 and spaced-apart in relation relative to the
first electrode plates 80 such that interstitial space exists
between each of the first electrode plates 80 and a corresponding
one of the second electrode plates 92. The second terminal 90
includes a second terminal block 94 electrically and mechanically
coupled to upper tabs 96 of the second electrode plates 92. The
second electrode plates 92 also include main bodies 98 and the
second terminal 90 includes a second terminal post 93. In certain
examples, the second electrode plates 92 can be coated with a
catalyst material of the type previously described.
[0107] The first and second sets of electrode plates 80, 92 of the
electrode arrangement 72 are coupled together by a plurality of
fasteners 100. In a preferred example, fasteners 100 are dielectric
fasteners that do not provide electrical connectivity between the
plates 80, 92. In certain examples, the fasteners 100 are bolts
that extend through openings defined in the electrode plates 80,
92. In certain examples, dielectric spacers 102 are provided on the
fasteners 100 at locations between opposing electrode plates 80,
92. The spacers 102 function to maintain a desired spacing between
each of the opposing sides of the plates 80, 92.
[0108] In certain examples, to discourage scale build-up, the
catalytic coating adapted for catalyzing the generation of chlorine
is not applied to the two outermost major surfaces 604, 606 (see
FIG. 11) of the conductive plates of the electrolytic cell. As
depicted, the outermost plates are defined by plates of the first
set of electrode plates 80. In other examples, the outermost plates
can be plates of the second set of electrode plates 92. The
interior major surfaces of the plates 80, 92 are preferably fully
coated with catalytic coating.
[0109] In a preferred example, the electrode arrangement 72 is
mounted to the lid 56 of the strainer housing 52. The terminal
posts 84, 93 can extend through the lid 56 and project
upwardly/outwardly from an upper/outer side of the lid 56. The
plates 80, 92 are secured at a bottom/under side of the lid 56 and
project downwardly from the inner side of the lid 56. When the lid
56 is mounted on the main housing body 54, the electrode plates 80,
92 fit within the interior of the housing 52 and within the
interior of the straining filter 62. During operation of the
on-board water system 22, the interior of the strainer housing 52
fills with water such that the anode and cathode plates 80, 92 are
preferably fully submerged within the water flowing through the
strainer 40. The electrode arrangement 72 is preferably coupled to
the lid 56 such that the electrode arrangement 72 is carried with
the lid 56 when the lid 56 is removed from the main housing body
54. When it is desired to clean the straining filter 62, the lid 56
is removed from the main housing body 54 to provide access to the
straining filter 62. When the lid 56 is removed, the electrode
arrangement 72 is carried with the lid 56 and concurrently removed
from the interior of the straining filter 62 so as to not interfere
with the subsequent removal of the straining filter 62 for
cleaning.
[0110] In a preferred example, water flowing through the strainer
40 flows through the interstitial space between the anode and
cathode plates 80, 92 in a direction shown by arrows 104 labeled at
FIG. 9. In certain examples, the plates 80, 92 are located within
the strainer filter 62 with open ends of the interstitial spaces
between the plates 80, 92, facing toward the opening 70 of the
strainer filter 62 and in alignment with the water inlet 58 of the
strainer housing 52.
[0111] In certain examples, the anode terminal post 84 and the
cathode terminal post 93 extend through openings 106, 108 (see
FIGS. 4 and 7) defined through the lid 56. In certain examples, the
openings 106, 108 can be sealed by gaskets or other seals that
provide a sealed interface between the terminal posts 84, 93 and
the lid 56. In the case where the lid 56 has a metal construction,
the sealing gaskets can provide a dielectric insulation layer
between the lid and the terminal posts 84, 93. In other examples,
the lid 56 can have a dielectric construction. For example, as
shown at FIG. 6, the lid 56 can have a composite construction with
an outer rim 110 having a metal construction and an inner portion
112 (see FIGS. 7 and 8) having a dielectric construction. In one
example, the inner portion 112 can have a dielectric construction
including a plastic material that includes polycarbonate. In
certain examples, the openings 106, 108 can be defined through the
inner portion 112.
[0112] Referring to FIG. 6, the outer rim 110 can be annular in
shape and can include mounting tabs 114 defining fastener openings
for receiving fasteners corresponding to the main housing body 54.
In certain examples, the fasteners can include threaded shanks 115
secured to the main housing body 54 of the strainer canister, and
nuts such as wing nuts 117 can be threaded on the threaded shanks
after the threaded shanks have been passed through openings defined
by the mounting tabs 114. In certain examples, a gasket can be
provided between the lid 56 and the main housing body 54 to provide
sealing.
[0113] FIGS. 7 and 8 further show the inner portion 112 of the lid
56. The inner portion 112 includes a main body 116 and a circular
ridge 118 that projects from the main body 116. In one example, the
ridge 118 can fit within an opening defined by the rim 110. An
annular shoulder 120 can be positioned around the exterior of the
ridge 118. The shoulder 120 can seat on a top side of the rim 110
and can be bonded to the rim 110. The terminal openings 106, 108
can be defined through a central region of the inner portion 112.
Fasteners 122 (e.g., nuts) can be threaded on the terminal posts
84, 93 to secure the electrode arrangement 72 to the lid 56.
[0114] It is desirable for the gas by-product of the electrolysis
that occurs within the electrolytic cell 46 to not accumulate
within the electrolytic cell 46. Example of gas by-product includes
hydrogen and other gases. To prevent the accumulation of gas within
the housing 52, it is desirable for the electrolytic cell 46 to be
deactivated when water is not flowing through the housing 52. When
water is flowing through the housing 52, gas generated through
electrolysis at the electrolytic cell 46 is swept out of the
housing 52 with the flowing water that exits the electrolytic cell
46 through the water outlet 60. However, if the electrolytic cell
46 is operating to generate biocide while flow is not occurring
through the housing 52, gas by-product from the electrolysis may
accumulate in the housing 52, which is not desirable.
[0115] In certain examples, the sensing circuit 254 of the biocide
generating system 24 can be configured for detecting the
accumulation of gas within the housing 52. When the sensing circuit
254 detects the collection of gas within the housing 52, the
sensing circuit 254 triggers the disconnection of power to the
electrode arrangement 72 (e.g., the processor 248 can open a switch
to interrupt the supply of electrical current to the electrolytic
cell 46). In certain examples, the sensing circuit 254 can include
a gas detection sensor for sensing a difference in properties
between a gas and a liquid (e.g., sea water). For example, one type
of sensing circuit can detect based on the higher electrical
conductivity of sea water as compared to gas. Such a sensing
circuit can use first and second electrodes that are electrically
connected to each other by sea water when the housing is filled
with saltwater, and that are electrically disconnected (e.g.,
isolated) from one another by gas when gas accumulates within the
housing 52. Essentially, a closed circuit exists when the
electrodes are electrically connected by sea water (which provides
relatively low impedance between the electrodes), and an open
circuit exists when the electrodes are separated by collected gas
(which provides relatively high impedance between the electrodes).
The sensing circuit monitors the connection state between the first
and second electrodes to determine whether the connection state is
an open or closed circuit. The sensing circuit can monitor
parameters which change when the impedance between first and second
electrodes changes. Example parameters include changes in current
flow and/or changes in voltage.
[0116] Other gas sensing systems/circuits can detect the collection
of gas based on the higher density of sea water as compared to gas.
For this type of gas sensing system/circuit, a float switch can be
used to determine when gas collects in the housing 52. The float
switch can include a float that moves with the water level in the
housing 52. The float is raised/lifted to an upper position by the
sea water when the housing is full of sea water, and lowers/drops
to a lower position when the sea water level drops due to the
collection of gas in the housing 52. The float switch changes
states when the float moves between the upper and lower positions
to provide an indication of whether gas is collecting in the
housing 52. Another gas sensing system/circuit can detect the
collection of gas based on the difference in optical properties of
sea water as compared to gas. For this type of gas sensing
system/circuit, an optical sensing system can be used to determine
when gas collects in the housing 52. The optical sensing system can
include an optical emitter and an optical sensor. An optical signal
sensed at the optical sensor varies based on whether gas or liquid
is present between the optical emitter and the optical sensor. The
variation in the optical signal can be used to determine whether
gas is accumulating within the housing 52.
[0117] A preferred gas sensor for the sensing circuit 254 includes
a gas sensing electrode 130 that senses the presence of collected
gas based on the difference in electrical conductivity between sea
water and gas. Preferably, the gas sensing electrode 130 is mounted
at a gas collection location of the housing 52. Typically, the gas
collection location is located at an upper region of the housing
52. When sea water is flowing through the housing 52, the upper
region of the housing 52 where the gas sensing electrode 130 is
located is filled with sea water. Thus, the gas sensing electrode
130 is immersed within sea water. When gas collects within the
housing 52, the gas displaces the sea water at the upper region of
the housing 52 such that the sensing electrode 130 is no longer
immersed in sea water and is exposed to the gas. In certain
examples, the gas sensing electrode 130 has a metal construction
that may include a metal such as titanium. In certain examples, the
gas sensing electrode 130 is mounted to the lid 56 of the housing
52. In certain examples, the gas sensing electrode 130 extends
through an opening 131 (see FIGS. 4 and 7) defined in the lid 56.
In certain examples, the gas sensing electrode 130 includes a
sensing portion 132 (see FIG. 3) located at an inner side of the
lid 56 which is adapted to extend into the interior of the housing
52, and a connection portion 134 (see FIG. 3) that extends outside
the housing 52. In certain examples, a gasket or other seal can
provide sealing between the gas sensing electrode 130 and the
opening 131 in the lid 56.
[0118] In certain examples, the first and second posts 84, 93 are
aligned along a plane P (see FIG. 6), and the gas sensing electrode
130 is offset from the plane P. Similarly, in certain examples, the
openings 106, 108 are aligned along the plane P, and the opening
131 for the gas sensing electrode 130 is offset from the plane
P.
[0119] In certain examples, the sensing circuit 254 senses
electrical connectivity between the gas sensing electrode 130 and
another component of the electrolytic cell. In one example,
electrical connectivity is sensed between the gas sensing electrode
130 and either the first terminal 78 or the second terminal 90. In
the sensing circuit 254 of FIG. 3, electrical connectivity is
sensed between the sensing electrode 130 and the second terminal
90. In this example, when sea water is flowing through the housing
52, the housing 52 is filled with sea water and the sea water
electrically connects the second electrode 76 and the gas sensing
electrode 130 together. When gas collects within the housing, the
sea water within the upper portion of the housing is displaced by
gas thereby exposing the sensing portion 132 of the gas sensing
electrode 130 such that sea water no longer provides an electrical
connection between the gas sensing electrode 130 and the second
electrode 76. Thus, an open circuit is formed between the sensing
portion 132 of the gas sensing electrode 130 and the second
electrode 76. By monitoring a parameter related to electrical
connectivity (e.g., voltage, impedance, etc.) and detecting changes
in the parameter, it is possible to identify when gas collects
within the housing 52. Upon detection of the collection of gas
within the housing 52 (which indicates a stoppage of water flow
through the water system), the control system of the biocide
generating system 24 can immediately terminate power provided to
the electrolytic cell 46 (e.g., by opening a switch) to stop the
generation of biocide and the corresponding gas by-products. In
other examples, the biocide generating system 24 can terminate
power to the electrolytic cell 46 for a predetermined time after
the detection of gas within the housing 52. The delay in
terminating the biocide generation after the detection of
accumulated gas can have a duration long enough for allowing enough
biocide to be generated for the biocide to diffuse from the
electrolytic cell to treat the portion of the water system located
before the electrolytic cell, and short enough to prevent the
excessive accumulation of gas.
[0120] In certain examples, the biocide generating system can
include a redundant system for determining whether water is flowing
through the housing 52. For example, a gas sensing system can be
used in combination with the flow sensor 51 and/or a pump operation
detector to provide redundant monitoring regarding whether water is
flowing through the on-board water system 22. One example flow
sensor 51 is shown at FIGS. 1 and 3 for sensing whether flow is
occurring along the flow path 32 and optionally for generating data
for allowing a flow rate through the flow path 32 to be determined.
The flow sensor 51 can include a flow meter such as a hall-effect
flow meter (e.g., electronic paddle flow meter). If any one of the
flow monitoring means provides an indication that no flow is
occurring within the system, the control system can disable the
electrolytic cell 46 of the biocide generator. For example, if the
flow sensor provides a no-flow indication to the control unit 48 or
the gas sensing system provides an indication to the control unit
48 that gas is collecting at the electrolytic cell 46, the control
unit 48 will disable the electrolytic cell 46. Similarly, the
control unit 48 of the biocide generating system 24 can interface
with the pump 42 itself (e.g., a pump motion sensor; a pump output
pressure sensor, a sensor that detects power drawn by the pump, an
operational state indication provided by the pump control, etc.) or
an on/off switch corresponding to the pump to determine whether the
pump 42 is on or off. When the control until 48 detects that the
pump 42 is in an off state, the control unit 48 can terminate power
to the electrolytic cell 46. In other examples, the system may
generate biocide intermittently or for controlled durations when
water is not flowing through the system (e.g., as indicated by the
flow sensor and/or gas detection sensor and/or the status of the
pump) so that biocide generated at the electrolytic cell can move
by diffusion to the portion of the water system located before the
electrolytic cell to discourage bio-growth at this region.
[0121] Referring again to FIG. 3, the control unit 48 of the
biocide generating system 24 provides power to the electrolytic
cell 46 for driving the electrolysis reaction that occurs at the
electrode arrangement 72. As shown at FIG. 3, the control unit 48
may include leads 150, 152 for coupling the control unit 48 to the
power source 262 on the watercraft 20. The power source 262 can be
a battery, generator, or other power source. In certain examples,
the power source can range from 12-240 volts and can provide
alternating current (AC) or direct current (DC). Preferred power
sources include 12 volt DC, or 24 volt DC, or 110 volt AC or 240
volt AC power sources. The control unit 48 of the biocide
generating system can include the isolation circuit 258 for
electrically isolating the power source 262 on the watercraft 20
from the electrical components of the biocide generating system 24.
For example, the isolation circuit 258 can transfer electrical
power from the power source 262 to the biocide generating system 24
in a manner where the biocide generating system 24 is provided with
the zero voltage reference 264 that is not electrically connected
to (i.e., is electrically isolated from) the earth ground 266 of
the watercraft 20. In one example shown at FIG. 15, the isolation
circuit 258 inductively transfers electrical power to the biocide
generating system 24 via a transformer that may include inductive
coils 159a, 159b. If the power source is a direct current power
source, the isolation circuit 258 can include an inverter 161 for
converting the direct current into alternating current which is
applied through the inductive coil 159a such that alternating
current is induced at the inductive coil 159b. A rectifier 163 can
be used to convert the alternating current induced at the inductive
coil 159b into a direct current voltage for use in powering the
various electrical components of the biocide generating system 24.
In the case where the power source 262 provides alternating
current, the inverter 161 can be eliminated. In an example
embodiment, the isolation circuit 258 is implemented using a VHB100
W DC-DC converter available from CUI, Inc. of Tualatin, Oreg. Other
isolation circuits, including other types of DC-DC converters
having different voltage thresholds, are useable as well. A voltage
regulator 249 can regulate electrical power provided to the
processor 248, the display 252 and other lower power components of
the system.
[0122] It is preferred for the control system to apply DC voltage
across the first terminal 78 and the second terminal 90. To
precisely control the amount of biocide generated at the electrode
arrangement 72, it is preferred for a constant current to be
applied between the first electrode 74 and the second electrode 76
for driving the electrolysis reaction. In certain examples, the
control unit 48 includes the cell power circuit 256 which includes
a constant current source 160 (see FIG. 15) coupled to a switching
device 600 which is connected to the first terminal 78 and the
second terminal 90 by leads 162, 164. The constant current source
160 receives a DC voltage input 181 from the isolation circuit 258
and is configured to drive a constant current across the first
electrode 74 and the second electrode 76. Preferably, the constant
current source 160 maintains a constant current across the
electrode arrangement independent of the load between the
electrodes as long as sufficient power is available. Additionally,
it is preferred for the constant current to be maintained despite
fluctuations/variations in the input voltage from the processor. In
certain examples, the processor 248 can control the constant
current power source 160 via a control line to vary the constant
current applied across the first and second electrodes 74, 76 based
on a water flow rate through the flow path 32. The water flow rate
can be determined by a reading from the flow sensor 51 or other
means. In certain examples, the processor 248 can increase the
constant electrical current with an increase in the water flow rate
and decrease the constant electrical current with a decrease in the
water flow rate so as to maintain a constant biocide concentration
(or at least a biocide concentration within a target range) in the
water flowing along the flow path 32.
[0123] Based on Faraday's law of electrolysis, the amount of
biocide generated through electrolysis is proportional to the
magnitude of the constant current supplied across the electrode
assembly. Therefore, if higher concentrations of biocide are
desired, the magnitude of the constant current provided to the
electrode arrangement 72 can be increased accordingly. Similarly,
if lower concentrations of biocide are desired, the magnitude of
the constant current provided to the electrode arrangement 72 can
be reduced accordingly. It will be appreciated that the magnitude
of the constant current provided to the electrode arrangement 72
can be modified based on water flow rate through the on-board water
system and other factors. In certain examples, the constant current
source 160 can include a resistance set 190 (see FIG. 15) that can
be changed between different resistance values by the processor 248
to selectively modify the magnitude of a reference current, thereby
adjusting the magnitude of the constant current output by the
constant current source 160.
[0124] Referring to FIG. 15, the cell power circuit 256 preferably
includes switching device 600 which is preferably configured for
alternating (e.g., switching, forward and reversing, etc.) the
polarity of the electrolytic cell 46 to inhibit the accumulation of
scale on the electrodes as previously described. The switching
device 600 can be configured in two different switch configurations
corresponding to two different polarity states (e.g., polarity
modes, polarity configurations, etc.) In a first switch
configuration (see FIG. 26), the switching device 600 couples the
constant current source 160 (FIG. 15) to the first terminal 78
(e.g., via lead 162) and couples the zero voltage reference 264 to
second terminal 90 (e.g., via lead 164). In the first switch
configuration the electrodes 74, 76 are operated in a first
polarity state in which the first electrode 74 is an anode and the
second electrode 76 is a cathode. In a second switch configuration
(see FIG. 27), the switching device 600 couples the constant
current source 160 to the second terminal 90 (e.g., via lead 164)
and couples the zero voltage reference 264 to the first terminal 78
(e.g., via lead 162), thereby reversing the polarity compared to
the first switch configuration. In the second switch configuration
the electrodes 74, 76 are operated in a second polarity state in
which the first electrode 74 is a cathode and the second electrode
76 is an anode. By reversing the polarity of the electrodes 74, 76
back and forth between the first and second polarity states during
time periods in which biocide is intended to be generated, the
accumulation of scale on the electrode plates of the electrodes 74,
76 over time is reduced. Preferably, the first and second
electrodes 74, 76 are temporarily electrically connected together
(see FIG. 28) before switching from one electrode polarity state to
another to provide an electrical short between the electrodes 74,
76.
[0125] In certain examples, the processor 248 of the control unit
48 can interface with and coordinate operation of the switching
device 600. For example, the processor 248 may control the
frequency in which the switching device 600 is switched between the
first and second configurations. While water is flowing through the
system, it is desirable for the electrolytic cell 46 to be
generating biocide. Typically, during biocide generation, the
electrolytic cell 46 will be repeatedly switched back and forth
between the first polarity state and the second polarity state. The
electrolytic cell is preferably operated for a first duration in
the first polarity state before being switched to the second
polarity state, and is also operated for the first duration in the
second polarity state before being switched back to the first
polarity state. In certain examples, the first duration can be in
the range of 3-5 minutes, but as indicated previously other
durations can be used as well.
[0126] To expedite the movement of ions in the electrolyte away
from the electrodes (e.g., equilibrating the ions in the
electrolyte) before switching the system electrodes between the
different polarity states, it is preferred for electrical power to
the first and second electrodes to be terminated (i.e., a
difference in electric potential is not provided between the first
and second electrodes) and for the first and second electrodes 74,
76 to be electrically connected to each other (e.g., short
circuited). In one example, the switching device 600 is operable in
a third switch configuration (see FIG. 28) in which electrical
power from the constant current source 160 is terminated to the
first and second electrodes 74, 76 and the first and second
electrodes 74, 76 are both electrically connected to each other and
to the zero voltage reference 264. The electrolytic cell is
preferably operated in the third switch configuration for a second
duration before switching to a subsequent electrode polarity state.
It will be appreciated that switching of the switching device 600
to the third switch configuration and the duration the switching
device 600 remains in the third switch configuration before
switching to the subsequent polarity state can be controlled by the
control unit 48. In one example, the second duration is less than
or equal to 1 minute, or less than or equal to 45 seconds or less
than or equal to 30 seconds.
[0127] FIG. 29 depicts an example switch arrangement 700 suitable
for functioning as the switching device 600. The switch arrangement
700 is depicted as having an H-bridge design including a first
switch 702, a second switch 704, a third switch 706 and a fourth
switch 708. In one example, the switches 702, 704, 706 and 708 are
transistors such as metal oxide semiconductor field-effect
transistors (MOSFETS). When the first and fourth switches 702, 708
are on (i.e., closed) and the second and third switches 704, 706
are off (i.e., open), the switch arrangement 700 is in the first
switching configuration in which the first electrode 74 is
electrically connected to power (e.g., the constant current source
160) and the second electrode 76 is electrically connected to the
zero voltage reference 264. When the first and fourth switches 702,
708 are off (i.e., open) and the second and third switches 704, 706
are on (i.e., closed), the switch arrangement 700 is in the second
switching configuration in which the first electrode 74 is
electrically connected to the zero voltage reference 264 and the
second electrode 76 is electrically connected to power (e.g.,
constant current source 160). When the first and third switches
702, 706 are off (i.e., open) and the second and fourth switches
704, 708 are on (i.e., closed), the switch arrangement 700 is in
the third switching configuration in which the first and second
electrodes 74, 76 are both electrically connected to each other and
to the zero voltage reference 264.
[0128] As indicated above, the sensing circuit 254 of FIG. 3 can
monitor a parameter related to electrical connectivity to determine
when gas collects within the housing 52. The parameter can relate
to electrical connectivity between the gas sensing electrode 130
and another component of the electrolytic cell 46 such as one of
the first or second electrodes 74, 76. As shown at FIG. 15, the
sensing circuit 254 can include a power input 290 for receiving a
direct current (DC) voltage from the regulator 249. The sensing
circuit 254 can include a regulator 292 for further regulating the
input voltage. The sensing circuit also includes an oscillator 294
that converts the regulated input voltage into an oscillator signal
(e.g., an AC signal) that is applied through a resistor 295 to a
lead 297 that couples to the gas sensing electrode 130. The
resistor 295 has a reference resistance. A blocking capacitor 296
ensures there is no net DC voltage on the electrode 130. Depending
on the position of the switch 600, at least one of the first and
second terminals 78, 90 is connected to the zero voltage reference
264 of the biocide generating system. A detector 298 compares a
resistance to the oscillator signal in the fluid between the gas
sensing electrode 130 and the first or second terminal 78, 90 with
the reference resistance. When saltwater makes an electrical
connection between the gas sensing electrode 130 and the first or
second terminal 78, 90, the sensed resistance between the electrode
130 and the first or second terminal 78, 90 is well below the
reference resistance. In contrast, when accumulated gas within the
electrolytic cell forms an open circuit between the electrode 130
and the first or second terminal 78, 90, the sensed resistance
exceeds a threshold resistance of the detector 298 and the
oscillator signal is directed by the detector 298 to a transistor
299 which activates a gate connection to the zero voltage reference
264, thereby causing a gas indicator signal to be sent to the
processor 248. Upon receipt of the gas indicator signal, the
processor 248 can open a power switch to stop power to the
electrode arrangement 72 and can activate an indicator (e.g., a
light, audible alarm or other indicator) on the display 252 to
provide an indication that gas has been detected in the
electrolytic cell 46. In example embodiments, the sensing circuit
can be implemented using an LM1830 Fluid Detector, available from
Texas Instruments (formerly National Semiconductor) of Dallas, Tex.
However, other fluid level detectors can be used in a manner
consistent with the present disclosure.
[0129] In certain examples, the processor 248 of the control unit
48 can interface with and coordinate operation of the sensing
circuit 254, the cell power circuit 256, the switching device 600,
the sensor 51, the user interface 250, the display 252, and the
isolation circuit 258. Additionally, the processor 248 can
interface with other pieces of equipment on the watercraft 20 such
as pumps, potable water systems, systems for filling bait wells, or
other systems. The processor can interface with software, firmware,
and/or hardware. Additionally, the processor 248 can include
digital or analog processing capabilities and can interface with
memory (e.g., random access memory, read-only memory, or other data
storage). In certain examples, the processor 248 can include a
programmable logic controller, one or more microprocessors, or like
structures. Example user interfaces can include one or more input
structures such as keyboards, touch screens, buttons, dials,
toggles, or other control elements that can be manipulated by an
operator to allow the operator to input commands, data, or other
information to the controller. The display can include lights,
audible alarms, screens, or other display features. An overheat
detection system may be arranged to output an overheat signal in
the event the temperature sensed by a temperature sensor or sensors
610 (see FIG. 15) is above a predetermined temperature. The
temperature sensors 610 may be used to help prevent active
components from becoming hot or overheating during use or failure.
The temperature sensors 610 may be used to detect when the
temperature in an engine room of the watercraft becomes too hot, or
when a temperature in an enclosure housing one or more components
of the biocide generating system (e.g., the processor 248 and/or
the sensing circuit 254 and/or the cell power circuit 256 and/or
the isolation circuit 258) exceeds a predetermined level. The
temperature sensors 610 can interface with the processor 248 and
the processor can control or modify operation of the biocide
generating system. For example, if the sensor or sensors 610
provide temperature reading indicative of an overheating condition
(e.g., if the sensor reading is above a predetermined value), the
processor 248 can implement a heat-reduction control protocol
designed to reduce or minimize heat production by the biocide
generating system. For example, the processor may cycle power on
and off to the system to control the amount of heat generated, may
reduce the electrical current provided to the electrolytic cell, or
may shut down the system. In one example, the system may be powered
off for at least thirty seconds, at least one minute, at least two
minutes, at least three minutes, at least four minutes, or at least
five minutes to allow for cooling.
[0130] FIG. 14 shows an example integrated display and user
interface module 400 suitable for use with the biocide generating
system 24 of FIG. 1. The combined display unit and user interface
module 400 includes a user input in the form of a knob/dial 402 for
allowing the user to vary the magnitude of the constant current
provided to the electrolytic cell 46 for driving electrolysis. It
will be appreciated that the knob/dial can be turned to change the
resistance value of the resistance set 190 of the constant current
source 160. The display and user interface 400 also includes a
power button 404 for allowing the user to turn the biocide
generating system 24 on and off, and an on-light 206 that is
illuminated when the biocide generating system 24 is turned on. The
power button 404 can interface with the processor 248 to determine
the closed or open state of a power switch of the system. The
display and user interface 400 also includes an inhibit light 408
that illuminates when the control system of the biocide generating
system 24 is inhibiting the production of biocide. For example, the
inhibit light 408 may be illuminated when a potable water system or
bait-well fill system that uses water from the water flow path 32
is activated and drawing water from the water flow path 32.
[0131] Referring still to FIG. 14, display and user interface 200
can also include a cleaning light 410 that is illuminated when the
biocide generating system 24 is actively generating biocide as
water flows through the on-board water system 22. Additionally, the
display and user interface module 400 can include a first pump
light 412 that is illuminated by the system controller when a first
pump of the watercraft 20 is actively pumping, and a second pump
light 414 that is illuminated by the control system when a second
pump of the watercraft 20 is actively pumping. The display and
interface module 400 can also include an air detector light 416
that is illuminated by the processor 248 when the sensing circuit
254 of the biocide generating system 24 detects that gas is being
collected at the electrolytic cell 46, and a cell light 418 that is
illuminated when the electrode arrangement 72 of the electrolytic
cell 46 is in need of cleaning. It will be appreciated that the
cell light 418 can be illuminated after a predetermined time of
operation of the biocide generating system 24 or based on a sensed
electrolysis efficiency of the electrode arrangement 72.
[0132] In certain examples, electrode arrangements in accordance
with the principles of the present disclosure have package sizes
that are relatively small so as to be capable of fitting within
water strainers or other types of housing that can be readily
incorporated into the on-board water systems of watercraft. In
certain examples, the electrode arrangements can have package sizes
less than or equal to 50 square inches, or less than or equal to 45
square inches, or less than or equal to 40 square inches, or less
than or equal to 35 square inches.
[0133] It will be appreciated that biocide generating systems 24 in
accordance with the principles of the present disclosure can be
incorporated into the on-board water systems of watercraft for
first-fit applications, and for retrofit applications. In the case
of retrofit applications, strainers having integrated electrolytic
cells can be used to replace existing strainers present on the
watercrafts in need of retrofit. Alternatively, a stand-alone
electrolytic cell can be integrated into an existing on-board water
system at a location before or after a strainer. In still other
examples, water strainer lids having electrode arrangements and gas
sensing capabilities integrated therewith can be designed to fit on
the main housing bodies of existing strainers. Therefore, to
provide a retrofit, all that is necessary is to replace the
existing strainer lid of a strainer already installed in the
on-board water system of the watercraft with a strainer lid having
an integrated electrode arrangement. In this way, the existing
strainer is retrofitted to have an integrated electrolytic cell
suitable for generating biocide in situ with the on-board water
system.
[0134] FIG. 16 shows another on-board water system having a biocide
generating system 324 in accordance with the principles of the
present disclosure. The biocide generating system 324 includes an
electrolytic cell 345 incorporated within a stand-alone housing 352
(e.g., an in-line housing). The stand-alone housing 352 has been
integrated into an on-board water system 322 at a location between
a strainer 340 and a pump 342. The on-board water system 322
includes an inlet 328, an outlet 330, and equipment 344 in need of
biocide to prevent the growth of bio-matter. The stand-alone
housing 352 includes a water inlet 358 and a water outlet 360. The
electrode arrangement 72 is mounted within the stand-alone housing
352. Baffles 375 can be provided for distributing the flow of water
evenly through the electrode arrangement 72. The stand-alone
housing 352 includes an upper gas collection location 353. A gas
sensing electrode 330 is positioned at the gas collection location
353. The gas sensing electrode 330 projects through the housing 352
and can be coupled to a control system of the biocide generating
system 324 by a lead. The terminal posts 84, 93 of the first and
second electrodes 74, 76 also project through the housing 352 and
are connected to a current source of the control system by leads.
In certain examples, the current source is configured to apply a
constant direct current across the first and second electrodes 74,
76 to drive electrolysis for generating biocide within the
stand-alone housing 352. It will be appreciated that features of
the control system of the biocide generating system 324 can be the
same as those described with respect to the control system of the
biocide generating system 24. The control system of the biocide
generating system 324 can interface with the pump 342 to determine
whether the pump 342 is on or off. When the control detects that
the pump 342 is in an off state, the control can terminate power to
the electrolytic cell 345. In other examples, the system may
generate biocide intermittently or for controlled durations when
water is not flowing through the system (e.g., as indicated by the
flow sensor and/or gas detection sensor and/or the status of the
pump) so that biocide generated at the electrolytic cell can move
by diffusion to the portion of the water system located before the
electrolytic cell to discourage bio-growth at this portion (e.g.,
the portion extending from the electrolytic cell, through the
strainer 340 to the inlet 328). The biocide may also move by
diffusion in a direction extending from the electrolytic cell
toward the sea-water inlet of the water system. In certain
examples, the system can be configured such that when the system
continues to generate biocide while the pump is not operating,
water from the electrolytic cell can move by gravity through at
least a portion of the water system extending from the electrolytic
cell, through the strainer toward the inlet. In this way, water
containing biocide can move by gravity into the strainer to inhibit
bio-growth in the strainer or other components of the water system
located before the electrolytic cell. In other examples, the pump
can be periodically reversed for a short period of time while the
system continues to generate biocide so that water within the
electrolytic cell containing biocide can be pumped in reverse
direction from normal operation through at least a portion of the
water system extending from the electrolytic cell, through the
strainer toward the inlet. The valve corresponding to the inlet of
the water system can remain open during reverse pumping. In certain
examples, the pump is operated in reverse for a short enough time
that the pump does not cavitate (i.e., the pump does not operate
long enough to draw all the contained in the water system between
the pump and the water outlet of the water system). In this way,
water containing biocide can be periodically moved/pumped into the
strainer and/or elsewhere in the water system before the
electrolytic cell (e.g., through the pump for examples of the type
depicted at FIG. 19 in which the pump is before the electrolytic
cell) to inhibit bio-growth. In still another example, a separate
flow line 343 (see FIG. 16) can be routed from a first location at
the electrolytic cell or after the electrolytic cell to a second
location at the strainer or before the strainer so that water
containing biocide can be directed through the flow line 343 to
treat the strainer to inhibit bio-growth. In certain examples, one
or more valves can be provided within the flow line 343. In certain
examples, similar flow lines can be included to provide biocide
treatment to other components of the water system located before
the electrolytic cell (e.g., the pump for configurations of the
type as shown in FIG. 19 where the pump is located before the
electrolytic cell).
[0135] FIGS. 19-22 show another on-board water system 422 having a
biocide generating system 424 in accordance with the principles of
the present disclosure. The biocide generating system 424 includes
an electrolytic cell unit 423 (i.e., a biocide generating unit)
including an electrolytic cell 445 incorporated within a housing
452 (e.g., an in-line housing). The on-board water system 422 also
includes an inlet 428, a strainer 440, a pump 442, equipment 444
and an outlet 430. A controller of the type previously described
(e.g., controller 48) controls operation of the electrolytic cell
unit 423. The housing 452 can be integrated into the on-board water
system 422 at a location between the equipment 444 and the pump
442, although alternatives are possible. That is, the housing 452
and the electrolytic cell 445 may be mounted after the pump
442.
[0136] Referring to FIG. 20, the housing 452 includes a water inlet
458 and a water outlet 460. The water inlet and outlet 458, 460 are
configured for allowing the housing 452 to be coupled/installed
into the water system. In one example, the water inlet 458 can be
defined at least in part by an end cap 457 and a fitting 459 (e.g.,
a hose fitting). Similarly, the water outlet 460 can be defined by
an end cap 461 and a fitting 463 (e.g., a hose fitting). The end
caps 457, 461 mount at opposite ends of a central housing structure
465 of the housing 452. The central housing structure 465 defines a
flow passage 467 (see FIGS. 21 and 22) which extends linearly
between the end caps 457, 461. The flow passage 467 extends along a
longitudinal axis 469 of the housing 452. The longitudinal axis 469
extends between the inlet 458 and the outlet 460 and is parallel to
a flow orientation/direction through the flow passage 467. As shown
at FIGS. 21 and 22, the flow passage 467 has a transverse
cross-sectional flow area 475 defined by a flow area boundary 471.
The flow area boundary 471 includes at least one curved portion 473
that curves about the longitudinal axis 469. In one example, the
flow passage 467 includes a portion or portions that are
cylindrical (see cylindrical portions 467a, 467b). The flow area
475 within the cylindrical portions 467a, 467b is defined by a
cylindrical flow area boundary 471 having a cylindrical curved
portion that circumscribes the longitudinal axis 469. The
transverse cross-sectional flow area 475 is the area defined by the
flow passage 467 when in a cross-sectional plane perpendicular to
the longitudinal axis 469.
[0137] Referring to FIGS. 21 and 22, an electrode arrangement 472
is mounted within the central housing structure 465 of the housing
452. A mid-region of the central housing structure 465 includes an
upper gas collection location 453 positioned above the electrode
arrangement 472. A gas sensing electrode 430 is positioned at the
gas collection location 453. The gas sensing electrode 430 projects
through the housing 452 and can be coupled to the controller of the
biocide generating system 424 by a lead. Terminal posts 484, 493 of
the electrode arrangement 472 also project through the housing 452
and are connected to a current source of the controller by leads.
In certain examples, the current source is configured to apply a
constant direct current across first and second electrodes 474, 476
to drive electrolysis for generating biocide within the stand-alone
housing 452.
[0138] As described above, the electrode arrangement 472 includes
the first electrode 474 and the second electrode 476. The first
electrode 474 includes a plurality of parallel first electrode
plates 480 electrically coupled to the terminal post 484. The
second electrode 476 includes a plurality of parallel second
electrode plates 492 electrically coupled to the terminal post 493.
The second electrode plates 492 are positioned between the first
electrode plates 480 and spaced-apart in relation relative to the
first electrode plates 480 such that interstitial space exists
between each of the first electrode plates 480 and a corresponding
one of the second electrode plates 492. In certain examples, each
of the electrode plates includes an electrically conductive
material such as a metal material as described above. In certain
examples, a catalyst coating of the type previously described
herein may be applied to the electrode plates. In certain examples,
the outside surface of the outermost electrode plates in the
electrolytic cell are not coated with catalyst to help reduce
and/or eliminate scale build-up.
[0139] As shown at FIGS. 21 and 22, the electrode arrangement 472
is provided with a staggered end configuration adapted to allow at
least one end of the electrode arrangement 472 to match (e.g.,
complement, follow, coincide with) the contour of the curved
portion 473 of the flow area boundary 471 defining the transverse
cross-sectional flow area 475 of the flow passage 467. The anode
and cathode plates 480, 492 each have a length L that extends along
the longitudinal axis 469, a height H is perpendicular relative to
the length L, and a thickness T that perpendicular to both the
height H and the length L. The heights H extend across the
transverse cross-sectional flow area 475. The plates 480, 492 are
sized with different heights to facilitate staggering the ends of
the plates 480, 492 at one or more ends of the electrode
arrangement 472 (e.g., the lower end is shown with a staggered
configuration as shown at FIG. 22). The plates 480, 492 adjacent
the center of the electrode arrangement 472 have the longest
heights and the plates 480, 492 at the outsides of the electrode
arrangement 472 have the shortest heights. The plates 480, 492
gradually transition in height from large to small in directions
extending from a center 487 of the electrode arrangement 472 to
outsides 489 of the electrode arrangement 472. Ends 491 (e.g.,
lower ends as shown at FIG. 22) of the plates 480, 492 are
staggered relative to one another so as to follow the contour of
the curved portion 473. For example, the ends 491 define a profile
that follows the profile of the curved portion 473. The staggering
allows the plates 480, 492 to more fully extend across the full
cross-sectional area of the transverse cross-sectional flow area
475 so that a larger catalyzed plate surface area can be provided
within the housing 452 as compared to if the plates all had the
same lengths. This can assist in extending the operating life of
the electrode arrangement 472. In other words, by providing the
central plates with longer heights, the central plates can extend
into a lower portion of the flow passage that would otherwise be
unoccupied if the central plates had the same heights as the
outermost plates. Such optimization of plate size, substantially
increases the electrode surface area, and therefore, increases
generation of biocide at lower current levels.
[0140] FIGS. 23-25 depict another electrolytic cell unit 523 in
accordance with the principles of the present disclosure. The
electrolytic cell 523 has the same basic components and mode of
operation as the electrolytic cell 423, except the electrolytic
cell 523 has an electrode arrangement 572 having first and second
opposite ends 591, 593 (e.g., lower and upper ends as depicted)
each having a staggered configuration. The electrode arrangement
572 includes first electrode plates 580 having differing heights
and second electrode plates 592 having differing heights. The
plates 580, 592 are interleaved. The heights of the plates 580, 592
gradually decrease in directions extending from the central plates
to the outermost plate of the electrode arrangement 572. The ends
of the plates 580, 592 at the first and second ends 591, 593 of the
electrode arrangement 572 are staggered relative to one another to
follow a cylindrical contour 573 of a boundary 571 defining a flow
passage area 575 of a flow passage 567 that extends through the
electrolytic cell unit 523.
[0141] It will be appreciated that the "height" of an electrode
plate corresponds to the dimension of the electrode plate which
extends across the flow area of the flow passage. In the depicted
examples, the "heights" are oriented vertically. In other examples,
the "heights" may be oriented horizontally or may be angled
relative to vertical.
[0142] FIGS. 30-41 show another electrolytic cell unit 823 (i.e., a
biocide generating unit) in accordance with the principles of the
present disclosure. The electrolytic cell unit 823 includes an
electrolytic cell 845 incorporated within a housing 852. The
housing 852 can be integrated into a water system (e.g., an
on-board water system of a boat) at a location between the
equipment and the pump similar to the positioning of the housing
452 within the system of FIG. 19. The electrolytic cell 845
includes an electrode unit 802 including first and second
electrodes 874, 876, In use, electrical current flows between the
electrodes 874, 876 through seawater flowing between the electrodes
874, 876 causing biocide to be generated within sea water via
electrolysis. The electrolytic cell unit 823 is configured to
minimize the occurrences and/or sizes of low-flow regions (regions
that encounter minimal to low water flow during operation of the
unit) within the housing 852. To enhance the uniformity of flow
throughout the housing 852, one or more baffles (e.g., see baffle
835) can be used to prevent water from "short-circuiting" directly
from the inlet to the outlet of the housing. Additionally, an inner
profile of the housing 852 and an outer profile of the electrode
unit 802 can be designed to generally match each other to inhibit
water "short circuiting" paths between the housing inlet and
outlet, to minimize dead flow zones within the housing, and to
encourage flow between electrode plates of the electrode unit 802.
The features to enhance flow uniformity improve the biocide
generation efficiency of the electrolytic cell and also assist in
inhibiting the accumulation of scale within the unit.
[0143] The first electrode 874 of the electrode unit 802 includes a
plurality of parallel first electrode plates 880 (see FIGS. 35 and
37) electrically coupled to a terminal post 884 (see FIGS. 31 and
32). The second electrode 876 of the electrode unit 802 includes a
plurality of parallel second electrode plates 892 (see FIGS. 35 and
37) electrically coupled to a terminal post 893 (See FIGS. 31 and
32). The first and second electrode plates 880, 892 are arranged in
a plate arrangement 883 (see FIGS. 35 and 37) in which the first
and second plates 880, 892 are interleaved with one another to form
a plate stack. Within the plate arrangement/stack 883, the first
and second electrode plates 880, 892 are alternated with respect to
one another and are positioned in spaced-apart relation with
respect to one another such that interstitial space 881 (e.g.,
gaps) exists between adjacent ones of the first and second
electrode plates 880, 892 in the stack. In certain examples, each
of the electrode plates 880, 892 includes an electrically
conductive material such as a metal material as described above. In
certain examples, a catalyst coating of the type previously
described herein may be applied to the electrode plates 880, 892.
In certain examples, major outside surfaces 893 of the outermost
electrode plates in the electrolytic cell are not coated with
catalyst to help reduce and/or eliminate scale build-up. As shown
at FIGS. 37-39, the plate arrangement 883 defines an outer
form-factor (e.g., outer shape or transverse cross-sectional
profile) having opposite planar sides 895, 897 defined by the major
outer surfaces 893, and opposite rounded sides 861, 863 defined by
staggered ends of the electrode plates 880, 892. The outer
form-factor extends axially between opposite axial ends of the
plate arrangement 883. The terminal posts 884, 893 are mounted at
one of the axial ends. The interstitial spaces 881 have open ends
865 at the opposite sides 861, 863.
[0144] The housing 852 includes a canister 851 having a main body
853 that extends along a central axis 855 between first and second
axial ends 856, 857. The main body 853 has cylindrical outer and
inner shapes 858, 859 that encircle the central axis 855. A
removable lid 877 mounts at the first axial end 856 and an end wall
879 encloses the second axial end 857. The end wall 879 can be
unitary with the main body 853. The electrode unit 802 can be
mounted to and carried with the lid 877.
[0145] A central cavity 860 (FIGS. 38 and 40) extends through the
main body 853 between the first and second ends 856, 857. The
central cavity 860 is sized to receive the plate arrangement 883 of
the electrode unit 802. Preferably, as shown at FIGS. 38-40, the
cavity 860 has a form factor with a transverse cross-sectional
profile that generally matches the outer form factor of the plate
arrangement 883. For example, the cavity 860 includes opposing
planar sides 831, 833 that correspond to the planar sides 895, 897
of the form factor of the plate arrangement 883, and also includes
opposing rounded sides 825, 827 that correspond to the rounded
sides 861, 863 of the form factor of the plate arrangement 883. In
one example, the planar sides 831, 833 of the cavity 860 are
defined by fillers 811 (e.g., inserts) (see FIGS. 31, 32 and 34-36)
installed within the interior of the main body 853 of the canister
851. The fillers 811 extend axially along the central axis 855 and
include planar surfaces 817 (see FIGS. 31 and 32) defining the
planar sides 831, 833 and curved surfaces 819 (see FIGS. 31 and 32)
that match the curved inner shape 859 of the main body 853 of the
canister 851. In other examples, the fillers 811 can be integrally
formed or unitary with the main body 853 of the canister 851.
[0146] The housing 852 also includes a water inlet 805 and a water
outlet 806 (see FIG. 33). The water inlet 805 and water outlet 806
can be formed in part by fittings coupled to the main body 853 of
the canister 851. The water inlet 805 and the water outlet 806 are
offset from one another in an axial orientation that extends along
the central axis 855 (e.g., the inlet and the outlet are positioned
at different axial heights or different axial positions along the
axis of the housing 852) and are preferably positioned on opposite
sides of the axis 855 and opposite sides of the housing 852 (see
FIG. 39). The water inlet 805 defines an inlet axis 807 (see FIG.
39) and the water outlet 806 defines an outlet axis 808 (see FIG.
39). The water inlet 805 is at the rounded side 827 of the cavity
860 and faces the rounded side 863 of the form factor of the plate
arrangement 883. The water outlet 806 is at the rounded side 825 of
the cavity 860 and faces the rounded side 861 of the form factor of
the plate arrangement 883. The electrode plates 874, 876 are canted
at an oblique angle relative to the inlet axis 807 and the outlet
axis 808. The open ends 865 of the interstitial spaces 881 face
toward the inlet 805 and the outlet 806.
[0147] The electrolytic cell unit 823 further includes the baffle
835 (see FIGS. 31, 32, 36, 38 and 41) for preventing water from
short circuiting through the housing 852 from the inlet 805 to the
outlet 806. The baffle 835 also can be referred to as a flow
diverter. The baffle 835 is preferably mounted within the cavity of
the housing 852 at a location opposite from the inlet 805 and at
the same general side as the outlet 806 (see FIGS. 39 and 41). The
baffle 835 is positioned at an axial location along the axis 855
that is between the axial location of the inlet 805 and the axial
location of the outlet 806 (see FIG. 41). As shown at FIG. 38, the
baffle 835 has a comb-like structure with a rounded base 836 that
conforms to the curved inner shape 859 of the main body 853 of the
canister 851. The baffle 335 also includes comb teeth 837 (see FIG.
38) that fit between the electrode plates 880, 892 within the
interstitial spaces 881. The baffle 335 projects inwardly from the
main body 853 of the canister 851 toward the central axis 855 and
preferably does not intersect the central axis 855. The teeth 837
block the interstitial spaces 881 and also maintain spacing between
the electrode plates. As shown at FIG. 38, the baffle 335 has a
depth d that extends into the interstitial spaces 881 from a first
side 813 of the housing 852 corresponding to the outlet 806 toward
a second side 814 of the housing 852 corresponding to the inlet
805. Preferably the depth d does not reach the central axis 855 of
the housing 852 such that a terminal inner edge of the baffle 335
is between the first side 813 of the housing 852 and the central
axis 855. Preferably, the depth d extends at least 50 percent of
the distance between the first side 813 and the central axis 855.
In one example, the baffle 335 connects to the fillers 811 such
that fillers 811, the electrode plates 880, 892 and the baffle 335
are secured together as a unit that can be inserted into the
canister 851 through an open end of the canister 851 formed when
the lid of the canister 851 is removed. The baffle 335 can connect
to the fillers 811 by a snap-fit connection. For example, retaining
portions 900 of the baffle 335 can snap within receptacles 902
defined by the fillers 811. At least one of the fillers 811 and/or
the baffle 835 can be keyed relative to the housing 852 to ensure
the electrolytic unit is loaded into the housing 852 at the proper
rotational orientation (e.g., see FIG. 36 where key 906 is shown
fitting within keyway 907). The electrolytic cell 823 further
includes an end plate 815 (see FIG. 41) that covers the axial end
of the plate arrangement 883 adjacent to the end wall 879 of the
housing 852.
[0148] FIGS. 43 and 44 depict another biocide generating system 24a
in accordance with the principles of the present disclosure. The
biocide generating system 24a has similar components as the biocide
generating system 24, and like components have been assigned the
same reference numbers. The biocide generating system 24a is
modified as compared to the biocide generating system 24 by
including DC power conversion circuits 253 for providing power
(e.g., non-isolated power) to components such as the processor 248,
the display 252 and a gas sensing circuit 254a. The gas sensing
circuit 254a is isolated from the main power system of the boat by
a dedicated transformer or the like corresponding to the gas
sensing circuit 254a (e.g., incorporated as part of an isolated
regulator 292a) Also, the biocide generating system 24a includes a
constant current source 160a that receives power from the main
power system of the boat, and which is electrically isolated from
the main power system of the boat (e.g., the main boat ground 266)
by a dedicated transformer or the like corresponding to the
constant current source 160a. The DC power conversion circuitry 253
does not convert power provided to the isolated constant current
source 160a.
[0149] The various examples described above are provided by way of
illustration only and should not be construed to limit the scope of
the present disclosure. Those skilled in the art will readily
recognize various modifications and changes that may be made with
respect to the examples illustrated and described herein without
departing from the true spirit and scope of the present
disclosure.
* * * * *